I spoke with a someone recently who uses gmail on his Android device. An ad at the top that resembles an email appears about a second after his real emails appear, timed perfectly to interrupt his attempt to tap and read his first email. Of course he immediately goes back if he makes the mistake, but google probably still charges the advertiser for a click.
(This doesn't happen on my phone but I am more likely to have configured it than your average user.)
I lived in Spain for a summer and my roommates there were definitively non-techy and had relatively slow internet.
I watched them every single night often multiple times accidentally click the ads that load above on youtube (about 1 second delayed, perfectly as they went to click). They would of course always click back once they noticed it, which with slow internet takes more time too and probably doesn't look as much like a bounce.
It's the perfect cover for Google. All the techies who would get outraged by something like this generally have fast internet and ad-blockers.
For me, that first "email" is not the ad itself, but the "promos" folder, tapping it only expands the promos folder, not any of the ads. It does appear a ~second after opening the app though. However, a ton of other things cause the same shifting-as-I-tap problem (not just ads) causing me to mistap on the wrong e-mail all the time. So it seems like garbage UI design more than anything else. UIs moving around while trying to interact with them is one of my biggest pet peeves.
Happens to me. Sometimes out of reflex I'll accidentally click it two or three more times before I have to resist muscle memory and wait for the page to completely finished jumping around.
(This doesn't happen on my phone but I am more likely to have configured it than your average user.)