It is a dollar and cents game, these box stores don't care where the product comes from, who it goes to, or how it is used. They are approached by suppliers, package deals are made, money changes hands, product gets shipped, stocked and sold. You do not have to be a big name to play, you can buy at the same level, you just have to commit to the quantities and show your US dollars, the seller does not discriminate. This is very evident when you look at Sears products, you will have no idea what engine is on their mower until they put it on the floor next season, buy a Kohler small engine, buy a Coleman generator, heck go buy an MTD product, or a Troy Built. The lawsuit by Honda was years ago the early seventies, Honda supposedly won, they are smart enough to realize they cannot spend that kind of money everyday to fight a losing battle in court. The copy infringement on small engines is only an annoyance to them, it isn't even a distraction now, companies all over Asia not only China are copying designs. Look at cars it is hard to tell if you are approaching a Hyundia or a Mercedes. GM had it so bad they had to partner with Chery in China, if you can't beat them join them, they build them as well and cheaper let's use theirs.
As far as returned motors, that is the North Americans greedy attitude that changed that, Lets face it, it was dishonest and unfair to the company. Blatant product misuse, expectation of complete reimbursement, and then boldly advertise what you are doing. Put yourself in those shoes, you are a US manufacturer or supplier, you provide a product, your customer knowingly destroys it, your customer expects you to reimburse or replace. In my business(s) I would rather lose you as a customer, than lose my business because of you as a customer, I will deal with and honor my loyal trustworthy customers.
The argument will be made that why not return them they allowed us, it was actually lazy employees that did not check the policy or look at the product on return. You know you went in there hoping not to encounter a sales person that would recognize the modifications you made (govenor removed etc)