Slitherine

Assuming that is, a cheesy move is OK under the rules but otherwise a bit suspect?

Had a situation today in which some Agrarian javelinmen were annoying some drilled hoplites to their front. Another drilled hoplite unit moves forward and turns 90 degrees facing onto their flank which means they are pinned to front and side. Of course the Agrarians can choose which unit to react to and fall back.
However, what is to stop me doing a 180 degree turn with the hoplites to their front thereby pinning only from the side which, given the rest of their battle line, would cause them more problems?

Didn't do it as seemed a trifle odd turning your back on the enemy, even though they can't charge and are no more likely to inflict shooting damage than if i was facing to the front.

Yes the rules allow this. You might say it is cheesy. I might say if you want to take hoplites out of the battle to threaten LF - up to you. Bear in mind the LF could pass a CMT and shuffle backwards with a slight wheel so they are just pinned - as long as they end up further from you that's OK. Then they'll be able to evade to their own rear if charge.

Cheesy isn't always a good idea!

So, let me see if I have this right. The Agrianians move way out in front of their main line and harass some hoplites. The hoplites know they can't catch the Agrianians so they pull back (turn 180) and lure the Agrianians into a trap (flanking unit). Sounds like the Agrianians are asking for it. If you are willing to break up your line to disadvantage some skirmishers, I don't see why not. If I were the skirmishers, that is what I'd want you to do. And, you are still going to have trouble catching them.