Personally, If I was a modder(and don't get me wrong, I've seen some of the cool mods being made on this forum, they're unique, innovative and some are downright awesome) I would NEVER sell any of my mods. I would possibly offer the instructions for free with a well written legal disclaimer. The few bucks you're going to make aren't worth the risk of the liabilty you're undertaking. I have 2 commercially available mods right now(going on 3). I have no idea if the sellers I bought from have any type of liabilty insurance to cover any loss I might incur from a failure of their product. Honestly, if one of the mods would explode/catch fire/damage my property and injury me or a family member, I don't know what I would do, but I certainly would not be happy. Selling a homeade, uncertified, unregistered, unlicensed product is a risky venture. There's a whole other "product Liabilty insurance" thread that discusses this issue. There may come a day when homemade mods are the only option we vapers are going to have. So, to the modders, keep modding, we need you, just be careful, preserve your knowledge for future use, and make sure you protect yourselves.
Did I mention my wife is a lawyer? There are liability issues to be considered, but there's also standards of implicit assumption of risk and the ability to "shrink wrap" agreements of waiver of liability (by opening this box, you agree to hold the manufacturer blameless for any injury to yourself or any other person, property, or domestic animal, and to assume any and all liability for future users, that might be incurred from use of the enclosed device, and to private mediation at your own expense of any and all claims under the laws of Commonwealth of Youarescrewed, yada yada yada."
It's also why I'm incorporating safety features from the very beginning, even in a prototype nobody else should ever use, so that in the event I find myself in court I can point to that fact as evidence of my good faith in not wanting to injure anyone. If I can think of a way that my product could be a danger, I will incorporate a corresponding safety feature or option (so turning the batteries away from the user's face and making sure there's a venting path, using a protection PCB, putting in a safety lockout switch, I'll offer batteries using safer chemistry and encourage the users to buy them, etc.).
I'm not going to be selling atomizers, eLiquid, or anything else that might be considered a medical device or consumable tobacco, I'm just selling a battery pack that some might choose to use with those items. They could also use it to power a flashlight, their cell phone, or with the right attachments jumpstart their car, that's not my concern.
Ever actually *read* the legalese in your owner's manuals? Sure, this is America, anyone can sue anyone for any damned stupid thing they can think of. But that doesn't mean they'll win. Before I, or more specifically, the LLC that manufactured their device with my labor under my supervision, can be sued, it has to have enough money to pay the plaintiff's lawyer, and by then it will have its own lawyers. *I* won't be selling anything to anyone, I'll just work for and own stock in a company that does.
--Dave