Originally Posted by
RevJim
So now I just ask politely when I hand over my passport:
"Could I ask a small favor? I'd like to request no entry stamp, to help me conserve pages."
I started that 3-4 years ago and I haven't had a single entry stamp since. If you are friendly and polite about it, it also has the side benefit of establishing that you are a nice person, and not one of the grumpy jerks behind you.

I tried this once last year in MCO and it earnt me additional interrogation and a referral to a secondary. At 2am.