That is a great rational for being lazy. Unfortunately, I doubt anyone will buy it. Just say "I'm too lazy to put away all my plates properly" and people will at least respect your honesty.
My gym is pretty awful about this in general. The last time I was there, i had to almost completely dismantle the squat rack to do squats. Some one had a step under the bar at its lowest setting with about 40 lbs of various weights on each side. I have no idea what you do with that, but it was really annoying to dismantle the step to move it, take all the weights off, reset the pegs, etc. just to do my squats. I don't mind moving the pegs, because we all use the squat racks for several different exercises, but leaving all the weights on the bar and leaving the step right in the middle of the rack is totally uncalled for.