I don't see writing a Cease and Desist letter in a questionable case as problematic. I'd think much harder before filing a lawsuit. The fact is, the letter puts the infringer on notice and ususally ends the trouble. The fact is, upon receipt of a lawyer letter, the prudent course of action is to consult an attorney and get some advice. This is just plain insulting.
Lawyers work for clients who feel they've been wronged.
You are probably someone who would suggest that a doctor has an obligation to operate on someone who CAN'T pay the bill, but that he shouldn't perform useful surgery for a paying patient unless it's a matter of life and death.