Giving away source files?

[SwedishJazz]

I've got two non-commercial for-print commissions on my hands right now; two people asked me to draw them something to hang on their walls. I'm a bit apprehensive about giving away the source files, since both commissions are the type that could easily be printed for profit (cute animals doing cute things, that will always sell). Most of my experience with commissions has been fanart or photo portraits, which aren't as easy to steal.

What would you guys do in this situation? Is there a tactful way of saying "by the way, once you find the printer you want to take this thing to, let me know and I'll send them the files)? I offered one guy that I could put the work up at Society6 for less than he'd have to pay for the commission and printing, but in exchange it would stay up there for sale (he mentioned he isn't very rich, so I tied that offer into that. Well, he would save up a good 25 dollars). Or would just asking to sign a contract - which I'd have no way of enforcing, as the commissioners and I live in another countries - do the trick?

[mobychan]

Why not print one version yourself and send that over?

[SwedishJazz]

Why not print one version yourself and send that over?

As I mentioned, I'm on a different continent. The shipping would cost three times as much and take a week at least, and it would arrive ruined.

[Kia]

can't you use online printing services like deviant art?

[SwedishJazz]

can't you use online printing services like deviant art?

I did mention I offered it to one of the clients. It seems like the best solution for now, but I thought that maybe someone coudl offer some advice for handling this issue in the future.

[Kia]

as an artist you should get used to your art being copied and used without your permission. always assume worse case scenario (in this case client can scan and share the printed medium) and stop wasting your hair worrying about such things, you can always declare copyright war with thieves.
put your signature on the corner and trust people. they might copy your art but leave the signature on it and that can bring you fame.

[Anne]

What Kia said.
Two other things to consider
1. selling stuff like that is actually not that easy so even if they did something like that chances are high that they won't make a lot / lose money on that.
2. they actually commisioned you rather than just download something from the Internet (and there're tons of cute things out there)

You can also get famous and sell limited signed prints people will want to buy regardless of delivery fees, that's totally possible.

[SwedishJazz]

Thanks for the advice, Anne and Kia! I suppose you're right, I should give the commissioners the benefit of doubt.