I guess it depends. If your prize for highest tipper is, say, a custom video (which is a time-consuming thing you will have to work on during your off-cam time), and this guy tipped specifically for a Skype show, then no, his tip should not be counted as high tip. Because think about it...if you counted his tip as HT, that would be "double-dipping," and now he's getting a Skype show AND a custom video from you. That wouldn't be fair to you.
I'm not sure if you're referring to MFC, btw? To avoid confusion on this, it'd be best if you explained this in your topic (I know they only give you so much room for your topic)/whiteboard/profile, so guys don't make the mistake of tipping and think they're getting a 2-for-1 deal.