You would rather people afk (or worse) instead of leave?

And once they do implement vote-kick, I guarantee you there will not be a lockout penalty when you get kicked.

Your idea will not work.

The design of lockout timer is something that's inconvenient so people don't quit if they don't have to, but also not excessively inconvenient as to incentivize people to screw over their group even more overtly.

Trust me, if someone wants to leave, it's better if you just let them leave. They're doing you a favor by leaving peaceably. They can do much worse.