You most likely do not feel bad when it is done to you because you do it. This is how it makes me feel because I do not - I feel like a foolish lemming who blindly gets on a line just because it is there while other more enlightened folks merrily go about their day, not bound by silly linear constraints.I don't abuse this but I don't think it's an issue really at Disney! It's my happy place. Every line I have ever been in families have gone in front of me to join their wife or husband and I have never once been bothered! This is a family friendly park where families go in different directions at all times of the day. We understand each other. I would never do it for every ride, and there are four of us only but I would not feel bad if it happened once a day or if anyone did it to me. I'm happy at Disney. I get it.
I do understand how I feel is my issue. I do not like wasting time and now I feel that I am wasting time waiting in line when there are so many ways around that.
I also feel for the cast members who cannot stop this practice. It puts them in a no win situation when groups ask to be let in the line to meet up with their family. Disney needs to fix this for the safety and enjoyment of others.
I will not put myself in a dangerous situation by confronting this. Someone selfish enough to cut a line to join their family may be selfish enough to make the situation escalate. Not for the cutter's safety and state of mind, but for me, my family, those around me, and the cast member. I will note the time & place and stop by guest services in my own time to discuss the situation.
Deliberate line holding is a selfish practice.