I think it's a silly thing to even try. I start equalizing as soon as my head is underwater. I don't wait for my ears to tell me they need it, and as a result I don't have any problems equalizing.
James, I really wasn't trying to test my ears. Just found out by accident. Normally, I feel the squeeze around the 2 metre mark and sometimes even earlier. Perhaps around the 1.5 metre mark. I know that if I lie flat on the bottom of the 1.4ish metre pool which I usually practice in, I'll feel a little better if I do a little swallow.