I'm grateful for this thread, as its been getting me to think practically about a problem I've got with my upcoming Muse gig.
I'm going with three other people. I'm going to be fine - I imagine any pit would be equal in intensity to Oasis, a tad higher than Foo Fighters, both of which I've been alright with (though I never want to go through the Country House/Song 2/Parklife experience ever again!) One of my friends is also an experienced gigger, and another is a very well-built person and will be able to deal with anything.
However, my third friend is a tiny, not-particularly-strong person, and whilst she would love to be the front would be overwhelmed, scared and would probably faint. I've been worrying about this, and I've considered things like having her on my shoulders, but that'll block someone else's view and I'll have to be more careful with my own movement.
Ultimately I think we'll probably have to use the lower tier seating, but I'm curious how deep into the crowd we'll be able to go safely.