Don't know why they wouldn't let people bring in tripods, but like you said, you don't want to schlep a lot of stuff around.
Do you have a monopod? That might come in handy for the Nikkor lens.
This sort of thing is why I've invested in fast lenses with image stabilization. They're pricey, but often let you shoot more often with natural light while leaving the tripod at home.
2012 550i / dark graphite / cinnamon brown dakota leather / dark wood trim / premium package / sports package + 19" W-spoke 332 wheels / active roll stabilization / sports transmission with paddle shifters
2012 335i coupe / space grey metallic / saddle brown dakota leather / dark burl walnut trim / premium package / M sport package with 19" Star-spoke 230 wheels / M sports leather steering wheel with paddle shifters / navigation / Park Distance Control