Eh, you are always at risk of being fired, too. You’d have to have some kind of data to make the claim that this risk is more meaningful than the 1000 other risks you take every day.
Otherwise you’re just accepting status quo risks blindly, and thereby letting the mob make decisions for you. That seems risky.
It doesn't matter if it's a common practice. It's whether you want to deal with the uncommon outcome.
The odds might be long but the stakes are high.
Imagine in the United States giving 2 months notice thinking you're a good guy doing a mitzvah for your employer and then getting walked out the door and having to figure out COBRA insurance and getting by on unemployment and maybe a PTO payout if you're lucky.