[aequitas]

For me the author can be considered a supplier instead of a customer. Maybe they don't have a legal contract stating the business relationship. But the business owner is using both the software and support of the author. That it is free shouldn't make a difference here.

[DarkWiiPlayer]

Not really; the user was clearly using the addon privately, not for his busyness, so he wasn't really supplying the busyness itself.