As someone who has worked with Chinese made IoT devices, I have seen this problem many times. The issue is a bad architectural design of the system where a camera is “bound” to a user account and even if the user returns that camera it’s still bound to their account, and adding it to another account afterwards doesn’t disassociate it from the other user. It’s just stupid things like this that are not well thought out that pop up in the multitude of cheaply made Chinese IoT problems that have flooded the market.
Believe it or not, this is the smallest security flaw in some of these systems/devices...
Not sure what I would recommend for non-technical people but if you are a bit tech savvy, rolling your own is very robust nowadays. Buy cameras that don't need to be setup using an app (I prefer DHCP/Ethernet with web console), block them from going out at the firewall level, stop all services like mDNS/uPnP on the cams, install Blue Iris or BlueCherry DVR on a $500 laptop with 8TB USB drive, install the iOS/Android apps on your phone, open the right firewall ports, and now you can remotely monitor and watch your house from anywhere, safely.
I have 30 days of footage for 16 cameras recording to a 4TB HDD. The entire setup cost me around $3k over 7 years (cameras were more expensive in 2013).
There is absolutely no way I will ever trust a camera that needs me enter my home wifi password using an app, which then sends the plaintext password to a .cn domain to generate a QR code that the camera scans to configure itself (looking at you MECO Wifi IP cams). Way too many people around the world are falling for these cheap cams.
Since most people lack your technical know-how or patience or budget to implement such a setup, do you have recommendations for alternative consumer solutions on the market that do it right?
Believe it or not, this is the smallest security flaw in some of these systems/devices...