Yes, I think it would be agreed upon, across the board, that not a single pinkie should ever truly be considered as a long term buy and hold. Even only a very select few OTC stocks really fit into that bill, for that matter.
In theory, a pink or grey sheet stock is only intended to be a stepping stone to the next level...OTCBB, and ONLY while in developmental stage.
For a company to continue as a pinkie past development stage, and more than 1-1.5 years, is a sign that they are content remaining non-transparent, as well as incapable of executing a successful business plan in a reasonable timeframe, which is two major red flags in themselves.