I love to test people using different means which may indicate their skill level, as a tank. I've met tons of RDMs who didn't even launch one Scatter during a dungeon lap or DRGs who never used their aoe OR Heavy Thrust (10% damage boost). Let's just say I am rather skeptical of other party members when I tank and heal.
Therefore I queued up as a DRK for the expert roulette to get some Verity and landed on Doma Castle. Got in and saw we had a SCH, BLM and RDM. Seeing the caster line up, I thought I'd test their abilites (along with the healer) by masspulling at start (some hate it, some love it). They did it magnificently compared to what I've seen.
As a thumb rule for seeing if a RDM, BLM or any other class/job knows how to prepare, I usually do a countdown on the first boss to see if they do something in response. So I pulled a 10 second countdown and as it hit the 5th second, the RDM popped Acceleration (guaranteed proc, same as Ammunitions for MCH) and actually started hardcasting Verthunder/Veraero, while the BLM popped Enochian and started casting Fire III. Because I usually don't expect it, I didn't prepare for the pull, so I pulled at the 1 second mark and got the enmity beautifully taken from me. Did pop Provoke as soon as I managed to get my enmity combo up, though.
Did some revision and pulled at the 5 second mark the last two bosses. When we were midways throughout Yojimbo (which ironically means "bodyguard"), the healer DCed, so attempting to reduce her damage taken (who knows, maybe a large influx of lag), I used The Blackest Night and casted it every time I saw the healer wouldn't survive a mechanic. We beat him without dying thanks to the RDM and his Vercures. Did feel bad for the healer as she most likely didn't get the Verity.
All in all, I love it (as a tank and a healer) when people know what to do with their abilities and make the best out of every situation.