[Steve0]

Fair enough, but please tell them that before they enter a contract with you. Don't take their cash followed by not providing a service for reasons not stipulated before accepting the money.

[toomuchtodo]

You would think "please don't be an asshole" would be common sense, but I suppose adding it your product description about you providing support is being explicit.

[jtmb]

Not only providing support, but unilaterally disabling the product they purchased after the fact. That should be incredibly explicit. And even then.

Just look at Ham Radio Deluxe.