Is it possible to run rm -rf / without root access? I see videos of people running rm -rf / on their android but they always run it with root access that is running su first so I tried doing the same on my unrooted phone by running rm -r -i / but then it 'promoted 'examine files in directory /?'  so I got scared because I was not sure whether it will erase my files or not so I would like to know if rm -rf / without root  erase OS files and brick my device?
First off, running rm -rf / is always a bad idea – but you probably know that already.

Second: Yes, of course you can run this even without root. But it wouldn't be able to delete all files, for multiple reasons:


it can only delete files where the user executing the command has permissions to. Those are, naturally, pretty few (except for on shared storage aka SD card)
parts of the file system are mounted read-only (eg. /system). Those couldn't even be deleted with root powers unless before remounted with write access.