I think it all depends on the tech in the store at the time. I brought my board in years ago and had them wax it because I was in a bind and not at home. I'm pretty sure he did one of those crap belt waxes. After that, I brought my board in to the same Sportcheck a day later and there was a different guy there who knew a heck of alot more about what he was doing. Offered to sharpen my edges, said he was going to do a full hand wax and even fixed by toe binding.
So I'd suggest going in and talking to the guy first and finding out exactly what he is going to do and if he knows anything about snowboarding himself. If they know what they are doing, I don't see why you wouldn't take advantage of a free wax. Just don't give him your board if he doesn't know anything about snowboards and just knows how to operate the skate sharpener. lol