That code is only telling you the light is on, its there to stop people just removing the bulb to get rid of the code. There has to be an underlying fault thats keeping it on, it won't go off till the system has no codes set and the system is clear. What code reader are you using?
You need to check all connections under the seats for clean and secure connections these are the usual culprits for airbag lights. The seat belt buckle pre tensioners are another likely suspect, they require a certain resistance to be present otherwise they fail and set codes. ensure their connections are intact and clean.
As to people removing the bulb to mask an airbag light activation, they soon find out that there is a led in the cluster that also lights up with the airbag bulb so that still shows with the bulb removed and its actually embedded on the pcb. To mask that they bung some chewing gum in the bulb holder to block the light from the led. MOT tester should spot the absence of the warning lamp when the ignition is turned on and probably fail the car because of it.