Someone posted this pic on Reddit so I don't know any insider info. My speculation: they're trying in whatever way they can to cut down on the ever-increasing wait times that people are putting in, helped in large part by SOLD and other line-sitters, which the theatre sees as getting a bit out of hand. So I'm guessing the unspoken aim of these are:
#1 - If the person who starts the line has to be there the whole time, the limit of the wait is human stamina. If the same person then also has to see and enjoy the show at the end of their endeavor, they probably don't want to be up for 30 hours.
(So in answer to your question, although this is just a guess, I think that in theory they are indeed trying to disallow the person who starts the line at whatever time being "relieved" by either a line-sitter or friend, or else this would negate the purpose of enforcing these rules. I don't know how it would be enforced in real life when the box office isn't open, but maybe they're hoping that people who are sticking to the rules will police any attempt at others "cheating".)
#2 - Stamina again; make it less comfortable, and people are less likely to want to stay for line.
#5 - In combo with the no-swapping, this seems to be aimed at culling hired line-sitters specifically.
Also, #4 is interesting -- I wonder if it means they're not going to stress people out by asking how many tickets they need before they reveal what is available.
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