Airbag light system calibration - battery disconnected - car storage

[PLP]

My car is with the dealer for repairs due to circular saw blade attack.
A few weeks ago, though, I had it in a body shop where the inner door panels were removed and car was painted.
Now, I have the airbag light.

I asked the dealer to clear it.

I was advised it takes 1-2 hours of their time to calibrate the system.
Question 1.
Ugh, what calibration?

Then, I was advised that replacing (i.e. disconnecting) the battery will result in system reset and they (dealer) have to re-calibrate airbags again.

Question Two.
Is that true?


As far as I can tell - get a Durametric and clear the code.
That was Question Three.
Happy Halloween.

Nice rhymes, huh? Duh...


EDIT.
Supplemental info.
Airbag light is on, because I believe the body shop removed the bags without disconnecting the battery first... "honest mistake".

Now, car storage. Why did I bring it up?
Because I was told to keep the battery connected and on the trickle charger.
I thought disconnecting it is OK. If I let the car sit for 5 months, why bother with trickle and all this crap. Disconnect the negative and let it be.
On spring connect and it should start right up.

Jeff, thanks for the response.