I'm considering the purchase of a folder but one thing stumps really me. Since the purpose of a folder is transportability, it seems to me that a bike with derailleurs would be problematic. If you're constantly folding and unfolding it, putting it down and picking it up, placing it in the trunk and taking it out, that the derailleurs would inadvertently get bumped even with careful handling. Derailleurs are so easy to knock out of alignment, no matter how careful one is, that it seems, despite the weight, internal gearing would be much sturdier and dependable.
What are your experiences?