...You are splitting the line between the average player/weekend giger and someone who has the oppertunity to be flown internationally to play gigs. If I was facing such a gig, I would use what was provided. But if I had a similar gig that was close enough to me that I could bring/use my own rig I would do so with out hesitation.
That would be my preference, if its not yours, thats ok. They make different color t shirts for a reason.
Absolutely correct. In fact, not using a rig that you know provides you with your (& the audience's) best sound (or at least the best sound you've found so far