That'd irk me too, probably not enough to make an issue of it though. Mind you, I'm also the sort that generally tries to avoid using disabled loos - I'll use the one in the parent's room but if that's occupied and I'm desperate I'll hightail it for the normal loos and just stick DS's pram half in/half out of the door in front of me (I do try to get a cubicle as far away from the main entrance as possible) while I do my business. Bit harder to do with any more than one kid in tow I'll admit.

I do think it's general impatience that leads to people indulging in quite selfish behaviour - I did have to chuckle at the look on a mother's face when I noticed her standing behind me in the queue for the loos with her little girl who was doing "the dance" and offered to let her go ahead of me despite my being very heavily pregnant. I think a stiff wind would've knocked her over she was so surprised