WHEN THE in-cabin boarding-boogie begins in the aisles before the takeoff of your flight -- when everything anybody can possibly backpack aboard is being hurled wildly into overhead bins or drop-kicked halfway under the seats -- how many carry-on bags, boxes, basketballs or stuffed raincoats do you try to stash into the nooks and crannies? Starting Friday, the game is going to get a lot more difficult because the rules will change: the Federal Aviation Administration has said airlines should limit the number of carry-on bags that can be stored above or below the cabin seats. Some airlines already claim they do, but most flight attendants have tried to be accommodating and have let their scofflaws off with a short scolding. But there are two reasons for expecting little in the way of immediate dramatic changes:

1. The FAA didn't adopt specific requirements limiting the number of bags or their size, leaving that to the airlines to enforce.

2. Most of us still will try to smuggle everything on board because we know what happens when you check any baggage at the counter; you're kissing it goodbye, with little likelihood of a reunion at anything resembling the appointed hour and location.

True, the carry-on game has been posing a safety hazard. Flight attendants cite the 1977 accident in the Canary Islands, when two 747s collided on the ground, killing 582 people; survivors told of having to climb over mountains of carry-on baggage to reach emergency exits. The problem isn't so much the volume, but whether it can be secured.

Unless and until airlines can a) produce passengers' checked luggage quickly at their destinations and b) not keep scheduling passengers on seconds-to-make, so-called connecting flights for which they have no reasonable chance at all of having their luggage make the transfer, they're not likely to get much cooperation with any new carry-on limits. Maybe they should adopt the old Greyhound system -- let passengers flip their bags into the underbelly of the plane before they board and pick them off at the other end. At least that might be one way for an airline to cut your losses until it can get its baggage-checking act in order.