Let's begin with waiting behavior.
Our confessionals must be virtually soundproof because I have never heard anything when standing outside them, and that means fairly close to the priest's side (not the penitent's). It's just the way the line works because otherwise we would be blocking a narrow aisle.
That said, as a matter of form, I find it extremely rude to stand or kneel unnecessarily close to the door, merely because it looks to be very inappropriate, to say the least, and it certainly is not necessary. That said (again), how does anybody know that such behavior is for the express purpose of listening to other people's sins? Most of us generally recoil at the prospect of hearing someone's sins; we don't want to, and in fact we are told not only not to repeat what we said in confession, but also not to repeat what our confessor said. Is it possible that the bad manners of others are related to ignorance and not to morbid curiosity?
As to The Seal, that would be shocking, given the penalty to the priest (automatic excommunication); pretty high risk stuff on his part, and certain a grave injustice to the penitent. But without disclosing private details, can anyone give the general circuмstances -- such as whether the sins mentioned were mentioned to the penitent? If they were mentioned to a third party, how was the penitent made aware of such a breaking of the Seal? (Again, if it's possible to explain without revealing anything uncomfortable regarding identities, etc.)