For safety, rapid charging, or other reasons, some batteries include a thermal probe and a contact for that. So it wouldn't be hard for the replacement batteri

For safety, rapid charging, or other reasons, some batteries include a thermal probe and a contact for that. So it wouldn't be hard for the replacement batteries to have yet another contact and this one wired to a part of the circuit board perhaps intended to be used only for testing during manufacturing but going hot thanks to modded firmware that matches a certain phone number or something. It only takes a few bytes of extra instructions to match a string and set a pin high/low on a micro-controller. Alternatively using a microcontroller inside that battery that is signaled through existing contacts would take even less wiring. The signaling code to activate the microcontroller would be a bit more complex, but since you don't care what happens afterwards you can still keep it small.