Interesting answers ...

My thoughts (and I have no horse in this race really, but from a sales savvy POV...)

Inferring or implying a potential prospect's dissatisfaction with his current vendor's (sponsor's) (product or,) program by name is at very least in poor taste and may be found to some prospects as offensive. e.g., you are an idiot for affiliating with __named sponsor___.

This is something I would never do especially in a blind sales solicitation. My thoughts is that it would exclude my prospects' further attention to my sales pitch in many circumstances.

What I do find interesting is that most people are not offended by a B2B solicitation, without prior business exchanges, as Spam.

You are the exception to the rule; The "cheese" as you call it does sell -- anyone with sales experience knows that that is just creating a sense of urgency -- look at most mainstream advertising; Hurry, offer end _date certain_ that is the oldest tactic in the world and it is still used today because it works ...