Somebody can explain me the use of the airframe tag?
You can buy it in almost every 'drone' shop but I cannot see a reason to replace it? It looks rugged to me.

I believe the primary purpose for this spare part would be to modify attachment of devices aft/rear of the aircraft. Several users have attached third-party components to the back of the Inspire:

PaulKerry Posted at 2016-2-20 03:17
Ah. Is that it in the picture? Not the neoprene battery jacket but the bit sticking out into which ...

Talk about a miss-labeled part. Here's what the OP is referring to:
http://store.dji.com/product/inspire-1-airframe-tag

terrylewis Posted at 2016-2-19 20:23
Talk about a miss-labeled part. Here's what the OP is referring to:
http://store.dji.com/product/i ...

Yes, that is the part I'm referring at.
I cannot think it's intended by DJI to attach third part accessories to it, but I do believe people would use it therefore.

Don't people attach GPS tracker there?

I purchased a spare airframe tag to have engraved with my FAA registration number and aircraft name...as a way to personalize my Inspire 1.  As it turned out, the plate is anodized aluminum; the engraving came out perfectly.

Maybe to put on their aftermarket case?

Aeromirage Posted at 2016-2-25 23:25
Maybe to put on their aftermarket case?

Thank for the input guys, but I haven't heard the real function.
Anyone from DJI?

I asked this question when the Inspires first came out and never got an answer from DJI yet.

Here's one installed on my Caseman case. I think it's a nice touch.

Derek Spear Posted at 2016-2-21 00:09
I purchased a spare airframe tag to have engraved with my FAA registration number and aircraft name. ...

That's the purpose I always understood for the part.