It isn't illegal to remove them. but yo may want to check with your insurance agent first. some of them wont pay for certain things from an accident if a factory installed safety device is removed.
some don't care either. new studies are showing that during an accident in cerain situations that airbags can cause more harm such as chest, neck, burns, and facial injuries during lower speed crashes, also a loss of vehicle control.
It's personal choice tho. me i'll leave them, i found the tray to be about useless... things (my cell phone into traffic) slide right off it... and out the window on a left turn, thats why i have the airbag back in.
Besides, noones mentioning the light always being on.