Really, the pitfall is that it won’t be enforced in a way that they anticipate that it will be enforced.  In other words, it won’t prevent an employee from doing something they think the employee will be prevented from doing.  If you use an agreement that is a one size fits all agreement, not tailored to your business or your legitimate business interests, it’s very likely a court would blue pencil it or amend it and revise it and then you really don’t control what it’s going to protect and what it’s not going to protect.