As for OP situation. I say no letting them cut the line. Either step aside and wait fro them to get through the line like everyone else, or just take the next slot and wait at the top for your family/friends
Another singles line
violation that irritates me is when a group of people cruises up the singles line and either
suddenly becomes a threesome or foursome at the front.. or even when they split up and ride as singles with other groups
instead of taking the line together like everyone else skiing together with others has to.