Thank you for your concern. I realize that you didn't have the whole story...
Our computer died on a very, very cold winter's day. No deployement, just death - I don't know the cause. There is "no one home" in the computer - no communications at all.
The dealer estimate was over $2400. They recognize that it is expensive and advised: "Don't bother having it fixed. You can still drive the car. There are a lot of older Mercedes out there with SRS lights on. If you should get hit, you've got the full Mercedes structural design, and are only missing the airbag..." Then they offered to have us trade the car in.
We like the car and wanted to pursue having it made whole again.
I contacted several "recylers" and was told that this OEM piece was from a rear ended 1995 E320 in which nothing triggered. He only buys cars that were rear ended and does a lot of parting out of the front end. I have a 30 day guarantee that the part is ok. The seller seems pretty honest. I, too, hope that we don't get in the situation where the part is bad and there is no recourse.
This recycled piece was a whole lot less expensive than the dealer price. I'll have the diagnostics done after the install. If it works, it will cost me about $350 including labor to have airbag protection. If it fails the diagnostic, I can try it again, being more specific with the seller. and still save about $2000.
Some may call it "cheaping out". I suspect that a dealership repair tech and an owner might disagree on where to buy the part as each is trying optimize different aspects of time, resources and money. An independed service tech, might be somewhere in between.
As an owner, I view the approach of trying a recycled part to be a "calculated financial risk" with an upside of $2000 and downside of a few hundred - and feel that it is worth making the effort.
If I were an independent repair tech, I would explain the upside and downside, but would not be averse to helping my clients save a few $$ - especially if the customer did the legwork to find the part. I'd realize that the customer would consider this to be "good service" and would appreciate the effort.
Thank you for your concern.