I mean, I'd do it if I was up against a really tough squad for MY squad to beat. Say, the enemy has a Corran + VI + R3A2 + Engine, and I'm running Phantom + Deci. I would probably just NOT engage with my Phantom, and run around like a maniac with my Deci, hoping to get 12 pts with that turret arc. It might be that my Phantom can find a time to engage then, but heck, I might NEVER decloak and attack, you know? At some point, you realize that your squad will not win a frontal engagement, and hope to god that you can pull out a lead with no problem.

But from personal experience, I have never seen anyone just run away after getting ahead, though I'm pretty sure I've played 1 or 2 games where my opponent SHOULD have done that.

I remember one specific moment for an enemy had GSP+PTL and a 2 hp falcon (PS9) on the table, and could have 3 banked the opposite direction and boosted instead of moving into range 1 of my 1 HP Soontir and 3 hp Whisper. He killed Soontir, but got a TL+F shot to the face with Whisper, losing him the match by >12 pts (the GSP was far away).

I once tried to outrun Chewie with Corran for a 1 point win. It wasn't really premeditated, and I wasn't going to slow down the dial phase, I was just hoping to get out of dodge for a few rounds during the last 10 minutes. I felt kinda bad, but his list was cheesy. He got me in the second round anyway, which I suppose was karma.

I say it's fair as long as its not your plan going in (ahem, some A-wing alpha strike lists).

I ran away in 1 game that I can recall and it wasn't that long ago. 1st time I played my Decimator. Paired with a Phantom against a double Falcon list for a tourney. Never really played big ships and 1st time using the Decimator so I naturally gun it straight in at one one the Falcons. It lasted like 5 turns but did enough damage that the Phantom finished off the one Falcon. His Falcon cost like 4-5 points more than my Decimator and with like 1 or 2 turns worth of time left on the clock, I ran instead of turning to fight(which I usually do. Blaze of glory thing makes for a fun game.).

Oddly enough, in games of the 40K Conquest LCG, I let my opponent take the last planet if he's winning rather than let him win by killing my Warlord at the last planet.

You can try to run, but at some point even the slowest Y-Wing will cut a corner or cross the diagonal and catch up to you. And while your running he will be sniping you at R3 and eventually you will lose a 25 point ship...and he wins 25-12.

Their is a reason why, with a few notable exceptions, the baseline stats on every ship favor more red dice than green.