You should have issues with this one, specially knowing it's a new mod which is paid, that means that it's not so interesting for spammers as they would have to code a robot for this mod only and knowing that it's not available in thousands of websites like a free mod

I'm not sure how this being a limited-release mod has something to do with spammers... I mean, maybe it's true, but the way I think of it is, if a spammer has a social account (and Twitter is full of spammers) then just a robot looking for social login buttons should do the trick, wouldn't it? It wouldn't have to be specific to this mod (though, true, a bot that looks for SMF *and* social login would be rare...)

It's really important as a robot without market is useless and no one is going to code it

This mod is doing great in terms of sales, but I doubt it's going to sell more than 100 licenses which would make it popular enough for something like it.

Summary: don't worry about spammers.  

Thanks for the feedback  I just got worried for an instant because a user with a suspicious name signed up and I thought "wooops!"  

Turned out it was a false alarm.

Glad to help