It's more of an IP thing.
If one bot is detected on an IP to be botting it can lead to a chain ban that affects other bots on the same IP.
I've heard people talk about separating caches as well, but I've never bothered.
Botting on 2 accounts on the same IP feels pretty safe. Maybe even 3. About half a year ago, I tried botting on 6 accounts on the same IP. Worked pretty well but I was chain-banned a month later. Whenever I made a new account on that same IP from then on, it was banned 15 minutes after tutorial island.