Oh this is cool, +1 for making this open to everyone, also +1 for making it in python and not making in in a flashy-shitty EXE file and basking in glory like MOST such tool creators do...
Anyway, the way that skype allows to check user availability is stupid and it just allows to information leaking such as this. But does block an IP after certain amount of checks? or you use tor for new IP each time so that microsoft couldn't see who'se abusing it?