One can love vintage and new stuff at the same time.
That's one aspect of why an endorser uses a different brand: the endorsed company doesn't offer a particular item, such as a vintage shell, a specific snare, or a certain cymbal (which is definitely the case with Paiste!)
I'm a bit guilty of this when I felt it was necessary. Specifically, when I endorsed Impact drums, they only offered a fiberglass snare. They were great snares, and very versatile, but when I needed an ringy, sharp, obviously metal shell sound for a track, I'd use one of the other brands for the song(s) in question. But good luck finding a picture of me with the non-endorsed brand!
The same thing happened occasionally with cymbals. Although I've endorsed Sabian since 1993, they never had a classic '60s Zildjian sound back in the day. Even Zildjian didn't offer it before fairly recently. So in town, I quietly used my old '50/60s Zildjians. Eventually, with Sabian's Vault series, I found that sound I loved for my blues & oldies gigs, and I changed them all out*. Ever since, I've been using Sabian, exclusively, for everything.
A drummer who is that sought after for 30+ years will have that many kits/snares/cymbals by different manufacturers it doesn't even bare thinking about.
An endorsement is just that, especially when you're at the top of your game.
And that's why an artist can (sometimes) get away with being seen with the non-endorsed brand. Their name has significant influence, and the company looks the other way, rather than lose the endorsement altogether. I like Steve Jordan, but I don't regard him as having that much influence, but Yamaha USA is apparently fine with it. It's a common case of the good outweighing the bad and, let's face it, business is business.
In both cases, I don't think it's cool to be pictured with the other product, even if it's vintage and the brand is long-gone and there's no obvious detriment to the current company. There's no reason to create the question that the artist might not really love the endorsed brand as much as he claims. Are credibility and ethics important to the young drummers out there who see these other brands? No, not so much. But it's
very important to the next company the artist wants to sign with. There are a handful of artists who can get away with it, and there are a few companies that don't care, as long as they have that name on
their roster.
Bermuda
* Sorry, my Zildjians, Paistes, Istanbuls etc are not for sale at this time.
** New abbreviation: In My Professional Opinion