If I am overlapped (which I always am) then I just tell the guy I'm closest to that I'm on his left or right, or I say, "I'm right here." I'm hoping that he'll now understand that I'm that close to him and won't make sudden or unexpected moves my direction because he'll go down if I go down. It's not really a strategy, but I guess you could say it's a "we're all in this together" mentality.
Of course, I talk a lot to the people around me during crits. I'm not enough of a threat that I'm giving away my position and I'm a firm believer that I won't crash if the people that can't see my position, can at least hear my position, especially in high speed turns. "I'm right here." "Don't squeeze me." "Hold it tight." Stuff like that.
Please don't take offense, but this is dumb. With this attitude, it's just a matter of time until someone breaks with your expectations and you end up on the ground. Never ever trust another rider to guard your front wheel for you. If you are in a vulnerable position, you are the one that has to take full responsibility for your own safety and notice if a rider is moving in on you and make the appropriate adjustments.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter