Thanks so much everyone for all of the replies.
I was wondering if it would turn into a concern for safety as opposed to the concern of butting in line.
I had actually purchased the ticket as a surprise for her when they went on sale, and then last Sunday she had her 18 month old reveal to us (through a note) that she was going to be a big sister....so I was like "UGH"! Once I did the calculation I knew it was going to cause problems.
Personally I was GA front row for 3 shows on the last tour and there was definitely some pushing, but I wouldn't think there is a concern for safety at a U2 show. It certainly doesn't compare to Metallica, Tool or even Tragically Hip mosh type pits. I would be surprised if I ever witnessed or heard of anybody falling or getting hurt at a U2 concert. However, just because I'm not the type to go nuts and push those around me, doesn't mean those around me aren't.
I imagine my sister *would* be fine, she's a health fanatic (she actually ran a 46 km race when 3 months pregnant with her first child), so she's in great shape...However if I can arrange it, it might be best if we could get seats instead. For this particular situation the ellipse random policy kinda sucks, it would rock if she had the freedom of being inside the ellipse.
Therefore, I will throw the request in here first....if anybody would like to trade some good seats for the SATURDAY show (even though I originally mentioned Fri) for 2 GA tickets for Saturday, please let me know. I will also be posting this in the "What do you want", "What do you Have", and that rockin U2 ticket trade database.