Yes, many bad ideas are possible to implement. At least temporarily. Until the next cleanup process figures out how to remove cadvisor dir regardless of file contents. Or the next OS release turns /tmp into a ram disk. Or… or… or…

Yes, it’s a fun academic exercise to think through possible mitigations. And in the end, it will still be dumb to keep this in /tmp

Why wouldn’t changing to permissions keep the file from being deleted by the internal process?

That’s like keeping your lunch laying outside on the sidewalk, getting stepped on by people and destroyed, and then wondering if your lunch would be safer if you put it in a stronger bag (but still left it on the sidewalk).

Don’t leave your lunch outside laying on the sidewalk, regardless of what you might do to “protect” it. Don’t keep important files in /tmp

I would wonder about leaching. Modern lead-free plumbing solder is safe for drinking water, but is silphos considered safe for drinking water?

I just did this. I installed a banana pi r4 as my main router with no wifi, and a couple of separate APs. I bought some Extreme Networks APs on ebay for USD$15 each, already flashed with openwrt.

I used the YouTube tutorials by OneMarcFifty to set up vlans for alternate SSIDs. Works great!