That's a good point, but it's not super clear what constitutes a valid folder name. A bit of googling turned up the notion that [anything other than the path separator](http://stackoverflow.com/questions/11417543/what-regex-pattern-describes-a-valid-unix-linux-directory) may be valid, and that it's kind of filesystem dependent.

We could check for the path separator easily enough, I think, maybe even disallowing both "/" and "\" just to be sure (and I'll add that). Beyond that, we may be better off just letting the install fail.