5d mkiii lack of built-in flash

My original thought behind my post about the need for external flash on the 5d mkiii actually pertains to the need for one while traveling on vacation.. i can't imagine having to bring along 3 lenses (wide zoom, normal zoom, and a fast prime) PLUS a flash while in Italy or Spain or anywhere else.. do people do this while traveling?

and that's my basic concern with the 5d mkiii not having a built in flash, for those few evenings when you might want one..

how do the semi-pro or serious hobby photographers here do it? thoughts?