[nicoburns]

This is why you have to do it every year. Which is exactly what a progressive taxation system does (or would do if it was a little more progressive than current systems)

[nonbel]

I imagine you would have to "do it" every week to have the claimed effect...

With online banking, etc perhaps once a day.

EDIT:

Actually, if the funds are transferred electronically it would take as long as an ACH transfer takes to get to the new account. The funds are tied up during that but then immediately available to the banking system again.