Well, on the last map before this one, there was always a big fight over 41. Every time I'd go out there, there's be 50+ enemy cons heading South to the island field (52?). I'd come from 44, so have a bit of time to climb out. I'd arrive over water near 41 at 10k (not too high), and see no less than 2 dozen low-alt cons heading S. Seeing that I'm usually in a 190a5 there's no way in hell I'm trading my safety to go into instant death at the hands of no less than 5 LAs, 6 spits, assorted 38s and 51s and even though those 3x formations of b24s are tempting I'd never survive to even get into guns range. In THAT instance I'm just going to turn back home, descend, come in lower and try to lure a small chunk of the horde off (say, just 5-6 planes) that I might someday, if I'm having the best day of my life, be able to cope with.
Sometimes they're not running from you, sometimes they're running from all the friends you have with you.
Other times they're just LA7 dweebs that don't bother engaging.