Facebook sponsored posts and Twitch ads are the only ones that get away with it that I've came across - and noticed at least. When you inspect FB sponsored posts' HTML they're very obscured indeed, there's sure no instance of "Sponsored" anywhere in the page's HTML. I haven't really tried but there doesn't seem to be any well rated "FB ad blocker" extension either, whereas you can block Twitch ads easily with a number of extensions. OTOH I've never understood how it can be so rare, even Google's cash cows are [killed by UBO](
https://imgur.com/a/fKJDKk2) from their own own store. To get away with it on mobile they had to gut
all mobile extensions, somehow without losing their kingly market share. Funnily enough, even if FB are pretty much the
only ones getting away from basic browser adblockers AFAIK, that segment is barely material for $FB as they get like 94% of their revenue from mobile anyhow (presumably quasi-all from the native apps).
If someone knows why obscuring HTML to force ads isn't more common practice, I'd be curious to know. I get it maybe for small websites that need the organic traffic (I assume Google would hit your SEO if your page structure looks like FB's), but how can it be so hard when it is indeed possible? I could understand if Google more specifically doesn't even try as they may lose adblocking nerds and they could use the data anyway, but I would expect to come across more sites that found solutions or clever ways of serving ads around UBO/ABP, at least make me use the picker. Is it really a colossal job to obscure ads and if it is reachable wouldn't medium-sized websites that find implementations remain unpatched for quite a while (big world out there)? Do you really need to own >$100B/Y business on godly margins or AWS to afford a fighting chance at that arm's race?