if the account gets banned then the games will be locked, but trust me, other than that, even if the owner deactivates the account you can still use the games as long as you dont sign into the account to finalize the deavtivation of your system. sure the account would be deactivated and can be reactivated on other systems, but you wont be locked out because the account would need to be signed in for it to get the request to lock the games
check this out:
You must login or register to view this content. i can confirm it works on the ps4 as well, i have been doing it since i got one