designate a meeting area outside but secure.
Or, (my way) make the lobby of your bedroom apartments "outside" & "light" by channeled out the z-levels above. dorfs that wants to get out from their bedroom will surely passed the place.
I did this once, thinking the same thing.
Then a siege showed up. Per modus operandi, I ordered Only Soldiers can go Outside. Some dwarves were caught in their bedrooms at the time. They were not pleased. Neither was I, since none of them could work while holed up in their rooms afraid to go 'outside'.
I'd recommend your sunbathing room not be somewhere critical. Stick a statue garden or a zoo outside. Not your booze supply. Unless you don't need to use the Outside commands to keep your dwarfs from wandering drunkily into a squad of marks gobbos.