Do you also give 40-50% raises to your employees every 2 years?

Everyone knows that you can and get those pay bumps if you switch jobs, but want to penalise it.

I will say this differently, if you see short stints as a bad thing, there are two options:

1) you want to explore people that have difficulties negotiating/interviewing

2) you will hire dumb people (because unless you are curing cancer, anyone that rejects 20-50% pay bumps every couple years is just dumb)