While I would personally never place a stand near someone else's (unless it was to make a point - like you shouldn't have put your stand near mine last year), it doesn't mean some scumbag won't put one near mine.

I'd make a decision based on the other guy - if he struck me as a true hunter, and if I believed he honestly didn't see my stand, I'd probably agree to his "I'll call you" offer - as long as he follows through.

On the other hand, if he's a sleazebag riding the coattails of my hard scouting, I might just empty an ashtray or two all around his stand and bury the butts under the leaves .....

No, I know it's not the "right" thing to do - but if the guy is a real jerk, he deserves whatever he gets.