Out of interest, where do you see their adverts?

Advertising doesn't need to be explicit. I won't comment further as I was roasted here when I wrote what I thought about the RPi Zero scarcity (which lasted years) when it was launched.

Sure, but that's normally the sort of adverting that goes along with a big advertising spend. I had imagined almost all their advertising exposure is from giving product away for people to review, and of course the charity aspect got headlines originally. I suppose you might say the silly low price of the pi zero was a form of advertising. I don't think they'll do a stunt like that again.