Someone upthread asked if it was really worth blocking people. For me, yes - it is. If line cutters have learned that because folks want to avoid confrontation, they will kindly step aside as they "excuse me" all the way to the front, they will continue to do it. OTOH, if they try "excuse me" and are told "no," resulting in them being unable to achieve their goal, maybe it will cause a change in behavior - NEXT time, they'll consider waiting in line like the rest of the guests.
Line jumping is unspeakably rude. And what astonishes me is that it's SO important to these folks to be with their families that they are happy to push past others waiting their turn, but when you suggest that perhaps the family could come back to wait with them, suddenly it's fine to wait separately.
(Had it happen at RnRC last month. A mom and her tween son pushed up behind us in the single rider line and asked to catch up with her adult son. Um, no. It's a SRL... so no bs excuses about "won't affect the number of rows" (which is totally untrue in many cases anyways) since its 1 rider = 1 seat. So I informed her that no, it was the SRL, so they wouldn't be seated together anyways, but he could certainly come back and wait with them if she'd like. She acted shocked that it was the SRL - the adult son (six or eight places ahead) turned around and yelled, "It's the single rider line, ma!"
Funny enough, they all chose to stay right where they were. And did it make a difference? Yep. The grouping room was cut between my party and theirs, and we were lined up in our train spots before the next group had emerged from the pre show.
Did I feel bad? No. If it wasn't important enough to them to line up together, why should it be important enough to me to disrupt my vacation?)
The ones that really get me are at RD... when we get separated in the crush and one member of our party has stepped aside to let ten minutes worth of folks pass, until the whole group catches up, only to be pushed past by untold numbers of folks who can't show the same courtesy.
It's a line. You get into the end of it... and you wait. It's a simple concept, and I wish Disney would take a hard line on cheaters. Because it's uncomfortable and frustrating for EVERYONE, even those who don't speak up.