If yesterday I queried your age and it said bracket < 17, and today I queried and it says >= 18.
CONGRATULATIONS! You've leaked the user's date of birth. Instead of protecting the user (specially children!), you've harmed them.
Malicious apps *will* query age every day.
Ubuntu & Elementary OS Linux distributions are planning how to implement age verification functionality (for all user accounts on their OS), in order to comply with a new California law.
“We're currently looking into how to implement an API that will comply with the laws while also not being a privacy disaster,” says Aaron Rainbolt, Ubuntu Community Council Member.
The current proposal is adding a new D-Bus interface (“org.freedesktop.AgeVerification”), which would impact all Linux systems.