Do you know that for a fact? Or are you assuming. I would think that would put MB under huge liability. They’ve built a bogus warning system and then use it to turn off a safety feature? And they charge you to re-enable the airbag?
If you mean "know it for a fact" because I either designed the system, tested the system, or had it fail to operate under the described conditions, the answer is no. If you mean know it for a fact because I have read it in multiple manuals from different manufacturers, the answer is yes.
I don't think that the warning system is bogus; the onboard computer has detected a sensor problem (the sensor was disconnected), it has signaled the error, and the operator is supposed to take the vehicle in for analysis/repair immediately. The workshop must review the system for proper operation before clearing the code/turning the system back on (or face liability if they didn't check it out, they clear the code, and it fails.) You may know that the reason for it going off is the fact that you disconnected the sensor, but no one else does.
In my 2017 Sprinter Operating Instructions, on page 181 under Display Messages, there is picture of a figure in a seat with an airbag going off in their face - "Restraint system Visit workshop" - the "Possible causes/consequences and > Solutions" text reads: The restraint system is faulty. If the restraint system is malfunctioning, individual systems could be triggered inadvertently or might not be triggered at all in the event of an accident. There is an increased risk of injury and accidents. > Drive on with care. > Visit a qualified specialist workshop immediately."
If the on-board computer has sensed a problem with the sensors for the Supplemental Restraint System (airbags and possibly powered seat belt retractors) then the on-board computer can't depend upon those sensors to determine whether it should activate the SRS. The warning light is telling the vehicle operator that the SRS system isn't functioning properly (i.e., airbags won't work [or will perhaps go off unexpectedly, but I think this is much less likely]) because there is a problem. For the manufacturer, there is less liability if the system to fails to function after an alert that it wasn't working correctly (as described in the manual) than for the system to just go off unexpectedly after the same warning. I personally would prefer the SRS to fail safe and merely not provide as much crash protection as I would like rather than to spontaneously go off while I was driving 70 MPH on a crowded interstate.
Here are a few Internet resources that agree with this interpretation:
https://www.openbay.com/articles/supplemental-restraint-system-srs-warning-light-on,
https://www.yourmechanic.com/article/what-does-the-airbag-warning-light-mean-by-spencer-cates,
https://svsautocare.com.au/road-safety/srs-warning-light-what-you-need-to-knowits-a-safety-issue/,
https://allaboutautomotive.com/blog/what-is-the-srs-light-that-is-illuminated-on-my-dash/.
The courtroom discussion might be:
Plaintiff: "<manufacturer> owes me a big settlement because the airbags didn't deploy when I was in an accident."
Defendant: "The onboard computer system shows that the SRS warning light was activated due to an error, and this code indicating that the system was malfunctioning was stored (reads out code). The vehicle was unsafe to operate as indicated in the owner's manual. The plaintiff chose to accept the risk of continuing to drive the vehicle."
Judge: "Case dismissed."
I believe that the reason for it being more difficult to "clear the code" for the SRS is to make sure that the system has been examined by a qualified workshop, and not just reset by Bill's Backyard Auto and Grits (no offense to any qualified workshops with this name intended). It costs money because the workshop is (theoretically) doing real work, not just clearing the code.