As the post says, dont let non specced tanks or healers que for those roles just because their class can have the ability. Would save me alot of wasted time.
The thing is.... the content isn't hard (LI HM excepted.)
I can comfortably tank any of the Tier 1 HMs in Vigilance spec, Soresu form and wearing my tanking gear. By comfortably I mean that even with a healer in mediocre gear we have no issues. My gear actually lets me tank it far more effectively than somebody in Corellia gear and tank spec. I even tanked HM False Emperor without wiping with just a Scrapper Scoundrel in bad gear (~16k health, without even 11 points in Sawbones - no SRMP even!) as our healer although that was a little bit too much like hard work.
Similarly, well geared healers are perfectly capable of fulfilling the DPS roles - we queued as a guild group with 2x Sawbones (good gear), Shadow Tank (mediocre gear) and Sentinel (good gear) and lost the Sentinel at the first miniboss. We continued without him, hoping he would be able to rejoin us, and didn't see a single enrage timer. Augmented Rakata/Black Hole healers can do better damage than Tionese DPS.
The issue isn't people queuing for roles they aren't specced for, it is them queuing for roles they can't handle which is generally a gear issue more than a spec issue. Probably any of the classes with a tanking form will be able to tank HM FPs in their dps specs as long as they have Columi tanking gear and swap stances.
Much more of an issue is when you get DPS who are wearing half Tionese tanking gear and half Corellia gear - they really struggle.