People do that all the time.
There's at least an article a year with a sad-looking Mum pulling a compoface mugshot in the Mail as "kid runs up huge roaming bill on holiday". It's easily done, especially in Africa where roaming agreements are extremely patchy. A few matches at 1080p, a bit of TikTok, and maybe a couple of software updates running in the background and you can easily get caught out.
It wouldn't be beyond the data networks to cut you off after a certain billing threshold is reached, but then they wouldn't make as much money from all the other customers who DON'T have high-profile jobs or run to the papers with their story.
It doesn't excuse trying to expense it.
Edit: I'm someone who ran up a £550 bill in East Africa last year, so I'm probably more sympathetic than most!