One of those weird situations where you both happen to had had the same code randomly assigned to each of your remotes. One of you (flip a coin) needs to re-initialize the remote. That way, you will be re-assigned another (random) code for your key fob.
Not sure how the 97 and 99 remotes get re-initialized. I know for my 94, I take the little chip out of the fob, place it in the alarm brain behind my glove box, push a button, and I'm set.
<span style='color:green'>1994 325i </span>- - - 75,000 mi.
No mods - - - very happy as is!
<span style='color:green'>1995 525i </span>- - - 154,000 mi.
No squeaks or rattles... unreal!