POINT:

Duncan Bannatyne, a British Multi-Millionaire and best selling author terminated his daughter’s interest in a trust after her caught her smoking.  

COUNTERPOINT:

In September 1993, Marin Cemenescu died leaving a will which stipulated that his wife must smoke five cigarettes per day for the rest of her life to inherit his house and $30,000.

The will provided that "She could not stand to see me with a cigarette in my mouth [and] I ended up smoking in the bathroom like a schoolboy.  My life was  hell."

 Blogging credit to Prof. Gerry Beyer

What kinds of conditions are enforceable?   What about a condition that the beneficiary shall not marry?  Or shall not marry a Catholic?  What about a provision discouraging divorce?

The general rule is that a trust can be created for any purpose that does not violate public policy (whatever that is).

It is generally accepted that in the case of a surviving spouse, a provision that discourages remarriage is enforceable.  

While they live parents certainly try to influence the behavior of their children, often with monetary consequences for reward ro punishment.  Why not after death?