I understand the logic behind it, but I disagree. If you are a very wealth person and your children decide to become volunteers for the red cross, you'll give them less money than if they decide to become bankers on Wall Street?
I think just setting up a baseline income for life would be sufficient. Say 100k/year. Enough that they can comfortably pursue whatever makes them happy, without being rich.
I know someone with that kind of plan, and it isn’t such a good idea: her, and her family pretty much fight over money a lot (and how to work around the situations unexpected by the trust fund rulings); they work soul-crushing yuppy jobs because they were raised to think 100k is nothing, and you can't live without 250, but they all have short-term gratification issues, meaning holding anything that makes 150k/y is near impossible. Most female members of that family can be described as gold-diggers that use the 100 as seed for that endeavour: you'd never suspect how expensive is the re-starter kit for that profession.