Lord, I didn't mean to give anyone ideas. My original post was to be funny - basically saying you couldn't get such a table unless you were willing to go 'under the table" if you will.
I will say, not knowing that employees couldn't accept tips does make me realize why it seems to work less often, but I have definitely seen it work, at 3 different restaurants. We don't get upset when people say they saw someone puking drunk in the bushes at Epcot, but apparently that happens too. I've seen this happen. Neither one is something you should probably expect to do at WDW.
Personal note: I'm on the dis, I get ADRs, I've never tried this, nor has any member of my party attempted this in WDW, because we didn't have to even try, as we could drink our cocktails while waiting for our reservation, or whatever, knowing we'll be seated. And, I certainly didn't know it was against the rules.