Above the VP level in certain lines of business at an investment bank, its typical to take 'gardening leave' if you move to a competitor. Typically it will be between 30 and 90 days, where the new firm must pay you, and you cannot speak to or do any work for them. Both banks will take it very seriously, and it's great work if you can get it. The feeling is that 1) Non-competes won't work in the environment; and 2) these people have intimate and specific knowledge of deals in the works on the banking side and positions on the trading side. 'Gardening leave' is a solution that make everyone happy.

As long as the employer doesn't trow you onto the street and threatens to sue you fair enough.

If they want that separation they have to be willing to pay for it.

Would work wonders in software development where the code is complex enough to be forgotten in weeks.