Is this just like another eBay where you can post your own ads and Selmer will take a cut of it?
I've only done a cursory look, but it looks like they're selling horns from authorized Selmer
dealers, like
https://www.raffaeleinghilterra.it, rather than
just Selmer Pro Shops. As Dan pointed out, it does say, on the Selmer website, "They have been serviced and adjusted with the utmost care by our craftsmen or by the best repairers from our certified network." You'd think that'd be Pro Shops, only.
If any of you live in the EU, particularly if you can read and write French, drop Selmer.fr a line and ask. Also, if anyone in the EU can just take a couple pics of their Selmer and
upload to their used horn linky, it'd be interesting to see the results.
This really isn't a trade in. It's just, "Sell it to us and we'll give you cash." We've actually had trade-ins for years: go to your local dealer/online dealer and ask if they'll put your horn towards a different horn. I've done this a number of times. Also, if you are trading in toward a (much) more expensive horn, generally the dealer will give you (somewhat) more for the trade-in than directly selling to him because the instrument that you're trying to buy has a markup.
I'm not sure why Selmer didn't do the full trade-in thing. I think it makes more sense than just selling used stuff.
Selmer's taking a cut somewhere. They're a company, after all. Companies are around to make money.