After Hanna Miller’s father developed dementia, he began repeatedly ordering items he had already bought. Food, toys and gifts kept arriving at his home, putting pressure on the Social Security benefits and pension that covered his rent and basic expenses. Miller and her friend Nikki Elbaz developed ShieldCart, a tool that sends shoppers to a simulated checkout instead of completing a real payment.
The product sits at the intersection of caregiving, household finances and personal autonomy. Miller’s father had a PhD in biomathematics and spent much of his career in the pharmaceutical industry, including time living overseas. He was known for his generosity and often traveled with suitcases full of gifts for his grandchildren. As his condition progressed, he could no longer remember purchases made just hours earlier, turning repeat orders from a family nuisance into a financial strain.
Repeat orders outpaced his limited income
Miller said her father repeatedly bought food online, with spending eventually exceeding what his limited Social Security benefits and pension could support. Those funds were largely needed for rent and other essentials, leaving little room for mounting online purchases.
At the time, Miller’s sister was her father’s caregiver and held power of attorney. The sisters tried canceling orders, changing his credit card and switching to a debit card to limit spending. But the changes unsettled him and led to repeated arguments. Miller worried that protecting his finances was also invading his privacy and taking away his ability to make decisions and give gifts.
“I kept asking myself, do I really have the right to make these decisions for him?” Miller said.
ShieldCart replaces payment with a simulated checkout
Miller had used ChatGPT but did not think she could build a product to stop unwanted orders on her own. She teamed up with Elbaz, who had more technical experience, to create ShieldCart.
The service displays a simulated page at checkout on participating shopping sites. It gives the impression that an order is being confirmed, but no real transaction is completed. Miller told her father it was an AI-powered security checkout app that checked orders for problems. For him, it preserved the experience of choosing and buying gifts without turning each attempt into a real expense.
Miller said the system helped her family save thousands of dollars over the course of a year during her father’s final months, while reducing the conflict that had accompanied canceled orders and payment restrictions. Elbaz said ShieldCart gave him back a sense of freedom to give generously.
Miller nevertheless struggled with the ethics of the approach. She was not simply canceling an occasional order; her father was using a checkout process designed to mislead him, without his knowledge. She sought advice from her rabbi, who compared the intervention to performing life-saving surgery while a patient was unconscious, arguing that the aim was to protect the person’s interests.
Miller sees ShieldCart as a way to intervene when necessary without openly telling a parent that their child is taking over their life. Her father did not have to hear, “You can’t make decisions anymore; I’m in charge now,” she said.
Caregivers can block sites or hold orders for review
Built using Claude Code, ShieldCart currently consists of a Chrome extension installed on an older adult’s computer and a desktop app where caregivers can review purchasing activity. Caregivers can block specific websites, much like setting up parental controls. In Miller’s father’s case, the family blocked cryptocurrency websites.
The product does not collect full credit card details. It asks for the last four digits of a card to make its confirmation page feel more like a real shopping process. Depending on the settings, an order can be blocked outright, put on hold or allowed to proceed before a caregiver reviews it.
That makes the software more than a payment tool: it acts as a layer of control between e-commerce, household financial management and caregiving. It may reduce repeat spending, but it also raises questions for families about who has authority, who can view purchase information and when someone may change an older adult’s device or shopping permissions without explicit consent.
Authorization remains a concern before wider testing
ShieldCart currently invites users to test the product by application. Miller and Elbaz advise families to consult an elder-law attorney or ensure they have valid power of attorney before installing the software on a relative’s device.
Miller acknowledges that the approach will not suit every family. Its use and acceptance may differ where adult children are estranged from a parent, or where a person is in an earlier stage of dementia and retains stronger independent judgment over shopping and payments. Whether the product can limit losses while preserving a person’s autonomy depends on the caregiving relationship and the authority in place.
Miller’s father died last month. His death came as a shock to the family because he had been in relatively good health. After taking time to grieve, Miller decided to keep developing ShieldCart and invite more caregiving families to test it.
ShieldCart plans wider testing and a mobile version
Elbaz said the team is looking to work with organizations that support people with dementia and their caregivers, while expanding the number of test users. ShieldCart plans to offer the service for free through the rest of this year and is developing mobile features for older adults who primarily use phones or tablets.
For Miller, a tool first built for her father has become another part of his legacy. She said that if it helps other families find a gentler way to manage repeat purchases, financial safeguards and an older relative’s dignity, the system created for her family can serve a purpose beyond an immediate household need.