I guess airbags in Europe are different. From here: http://www.raa.net/page.asp?TerID=299 (bolding mine)
Dog80, I think charizard answered your question, but at the risk of redundancy:
Passive restraints [those which are engaged without any action on the part of the user] are mandatory. The choice [of passive restraints] has been, and as far as I know still is, either air bags or automatic (motorized) belts [which are seatbelts that automatically position themselves around the user when the door is closed].
Obviously for this to make sense the air bags need to be operative even if the [regular non-motorized] seat belt is not fastened. Even so, air bags here in the states are often called SRS, and it is recommended to always use the seat belts. The automatic belts have a major flaw, in that only the shoulder belt is motorized. The lap belt still must be positioned and fastenend by the user. So as usual, the government gets involved and in the process of solving one problem (deaths and injuries due to not using regular seat belts) manages to create others (deaths or injuries from air bag deployment, and injuries from people sliding under the automatic shoulder belt if they don’t apply the lap belt), which are arguably worse than the original problem.
At first the choice was some type of passive restraint. When the regulation first came out there was a choice of which the car maker used. IIRC the three that were widely used were
Airbags
Motorized belts*
Stationary belts** (belt fastens to car door, you climb in underneath)
After a few years, airbags had become the restraint device of choice, and since about 95 or so are required by law here in the US.
*Note to people who drive cars with motorized belts: The shoulder belt is not fully effective unless you have the lap belt fastened. If you do not fasten the lap belt, there is a very real possibility that you could slide out under the shoulder belt, and have your larynx crushed by the shoulder belt. This happened to a young lady in my town a few years ago.
**Note to people who have stationary belts: This type of belt can eject you from the car if the door pops open! Make damn sure the door is fully latched every time you drive.
and
Airbags are referred to as supplemental restraints, but they will function either with or without a seatbelt. What drove the legal requirement was that back in the early 80’s there were no mandatory seat belt laws in the US. So the passive restraint rules came into force starting with the 87 MY. Since then every state has passed mandatory seat belt laws, and well over 75% of the drivers in the US are now buckled up.
So do airbags help when used with seatbelts? You bet they do. I have seen cases where people are now living through what 20 years ago would have been a fatal accident. But anyway you slice it, airbags are not a replacement for a 3 point seat belt. The 3 point belt is the single most effective safety system ever installed in any car.
[bragging hat on] The 3 point seat belt is a Volvo invention, by a young engineer named Nils Bolin. Nils passed away recently, but his legacy lives on[/BHO]
Gary when you wife is riding with you in a dual airbag car, make sure the passenger seat is as far back as possible. This will most likely put her out of range from the passenger bag and prevent injuries. When she is driving, it is important for her to sit with the steering wheel as far away as is comfortable. To be blunt if her tits are getting tangled in the spokes of the wheel, she needs to move the seat back. 
Ideally she should be sitting with her elbows just bent when holding the wheel at 9 and 3.
Also it should be noted that over the last several years depowered, or advanced airbags having been arriving on the scene.
since about 2001 our cars use various stages for deploying the airbags, and belts. We also use up to three different stages on our current bags. Now we even adjust for a short driver to low the inflation force.
“Stationary belts** (belt fastens to car door, you climb in underneath)”
Ah yes, thanks, Rick, I forgot about those. Or more likely, tried to blot them out of my memory. They were a pain in the neck to deal with.
Does anyone make a vehicle with motorized belts anymore? I haven’t seen any in a long time.
Boy you got that right.
My father had a late 1990s Nissan pick up where you could deactivate the passenger side airbag with a turn of the key. A pick up might not suit your style, but it’s an option.
Rick, I stand corrected, but I will state that shops which do illegal modifications to cars are fairly common, at least in this neck of the woods. If there’s no state inspection of the components in question, many smaller shops will happily remove the components for you. They will not keep service records of these modifications, of course, but they will do them, even though the legal penalties for doing so are quite severe.
KRM, if anybody does, I’d suspect that it’d be one of the smaller manufacturers (like Lotus, which did have an exemption at one time for not installing airbags on cars they imported to the US), as it is simply too expensive to keep parts for both decapitating – err – automatic seatbelts (which tended to fail early in life) and airbags.
First off do not ever confuse a pickup truck with a passenger car. From the feds point of view they are two totally different animals. Your father’s Nissan only had two legal seating positions, the driver’s seat, and the passenger’s seat (King cabs are not considered legal seating areas. I know they have belts, and all but they are not legal seating areas.) Therefore if you transport a child, it would have to be in the passenger’s seat, and therefore there must be a way to disable the airbag. That is why pickup trucks have on off switches for the passenger bag.
As far as a shop doing illegal mods goes, sure there are probably hundreds of them. However I still would not want one of these untrained, under-educated, idgits working on my car. YMNMV of course. Like I said I am picky about who touches my ride. They have to me my standards, which are much higher than most poeoples.
So what about two seat cars like a Miata?
Well, I wouldn’t call a guy who can hold a part in his hand, look at it, and say that it’s the wrong part for a car even though the car’s not there, and the difference between the wrong part and the right one is that one is about .050 inches longer than the other, all without looking at a manual or part number, an idiot, but to each his own.