Understandable if you can't avoid it just the one time. But isn't it always the one time when you get caught at it (like rolling through a stop sign or speeding?)
Anyways, I don't think the staff would appreciate it if during each session each and every person were to drop his weight once.
Clearly, there's a difference of opinion as to what a training session should be like. So we should probably agree to disagree here. Different if it was a gym with one of these lunk alarms or had a strict 'no dropping the weights AT ALL' rule i.e. 'no one train with a high intensity, all workouts should be a moderate or low intensity because we don't want to intimidate the other members with any loud noises.'
It's a gym. They have weights. In my gym, they have quite heavy weights. If you have heavy weights in your gym your going to attract local guys who like to lift heavy. That's a fact and is one reason a lot of commercial gyms only have DB's that go up to 80lbs (ish) - anyone who lifts properly / seriously is going to be held back by that. Same with no chalk rules, i don't believe for a second that it's anything to do with cleaning up - it's because they don't want guys in the gym who lift a lot of weight.
If you have the equipment that's going to attract proper weight lifters with strength and/or size goals, then weights are going to get dropped, people are going to grunt occasionally. If you have guys that are deadlifting 500lbs, then I'm afraid to say that there's going to be a little noise when the bar makes contact with the floor on the way down.
It's the nature of the game. If staff aren't going to 'appreciate that', then they either should make a strict rule (which it isn't in my commercial gym and yes, weights do get dropped all the time), or better yet, make it a rule AND get rid of all the heavy weights (the really heavy weights that the average gym goer will never pick up).