This isn't the best way at all – you're going to end up with a candidate who wants/is able to agree to that, instead of a potentially much better candidate who

This isn't the best way at all – you're going to end up with a candidate who wants/is able to agree to that, instead of a potentially much better candidate who won't. Since I'd wager that the vast majority of skilled engineers would reject that offer outright, you end up really shrinking your pool of talent.