let me be the first in this thread to admit (and yeah I know there are other posters in here as well who have done the EXACT SAME THING) that I have done this before. That is I have been one of the ones holding the entire row..
and it is bullshit. but, if it makes you all happier, I have made demands and the theater has made changes.
first some clarity though. for star wars in specific (ep1and2) no one of mine has EVER arrived to the theater after the line was let in. in other words this ISN'T me for a star wars movie. everyone is usually there for the movie a good 3 hours before the movie (just so you know the line usually starts about 18 hours before the movie).
anyway, I used to do that, got tired of getting glares from people, so started telling people that they needed to be there shortly after me. I will usually only hold a up to 10-15 minutes before the show now (for normal shows). If you aren't there within that time you can find your own spot to sit. so I have curbed it so that I'm not holding a whole empty row (which was rare anyway) five minutes before the show.
also, the theater by us changed (about three years ago ironically) so that you can only hold two seats per person and you can't hold any seats five minutes before the show starts. so if a row is seats, you would need at least 4 people to hold the entire row, three people to hold the entire row except for 1 seat. and anyone who isn't there within the last five minutes has to find their own seats.
as for my thought on why h9olding numbers of seats is ok.. well, I usually get to a big midnight premiere by 8 in the morning. it is assumed that the first 20ish people behind me will get pretty much their choice of seating give or take a few rows. the thing is, the first 20 people behind me don't usually fill up until say noon or so.. that is PLENTY of time for the whiners to get there and get the same privilege.
so is holding an entire row of seats bullshit? you bet. but am I going to cry for the people who get there 12 hours after the line started and want to sit in the THX certification zone that is being held out by 3 people? fuck no!