Read the Lanham Act instead of a blog post https://www.law.cornell.edu/wex/lanham_act https://www.law.cornell.edu/wex/lanham_act The real answer is 'it depends

Read the Lanham Act instead of a blog post https://www.law.cornell.edu/wex/lanham_act https://www.law.cornell.edu/wex/lanham_act The real answer is 'it depends,' there is no pat hard and fast answer about the obligation to enforce a trademark. Also it becomes more ambiguous because trademark cancellation proceedings are quite expensive in terms of time and legal fees. You can do a lot of naughty things and get away with it if the prospect of fighting you in a cancellation proceeding becomes too daunting and expensive. The possible workaround is to get a declaratory judgment invalidating the trademark but that is not necessarily something achievable in most situations.