I haven't been at this homebrewing thing for all that long, but I find that the standard advice to bottle after 3 stable gravity readings is about as foolproof as the pull-out method of birth control.
I've seen brews drop anywhere from 2 to 6 pts after bottling (then gushing when opened), even though they had stable gravity readings in the fermenter, sometimes for weeks before bottling.
I have become an advocate of doing a fast ferment test (FFT), especially on any new recipe / mash schedule / grain bill (or extract type/brand) you might try or develop, and certainly anytime you suspect you might have a stuck fermentation. I'm surprised that FFT is not referenced more on this forum, I think it could solve--or better yet, prevent!--many of the gusher issues new brewers have.
Some reading on FFT:
Post #4 in this thread shares some practical experience I've had dialing in carbonation on bottled brews that did not reach true FG:
(BTW, my numbers are empirically derived using excellent sanitation, a digital refractometer and a Zahm-Nagel carbonation tester. Working in a food and beverage lab does have its perks!)