An easement is a right in the land of another. A license only gives one a personal privilege to do something on the land of another. Easements also differ from licenses in that they are "attached" to the land. This means that the easement will continue even if the property subject to the easement gets transferred to a different owner. A license is not an interest in land, but is a privilege to do something on the land of another person. Upon the sale of the property, subject to the license, the license terminates unless a new license is executed.
Courts vary in their approach to enforcing releases depending on the particular facts of each case, the effect of the release on other statutes and laws, and the view of the court of the benefits of releases as a matter of public policy. Many courts will invalidate documents signed on behalf of minors. Also, Courts do not permit persons to waive their responsibility when they have exercised gross negligence or misconduct that is intentional or criminal in nature. Such an agreement would be deemed to be against public policy because it would encourage dangerous and illegal behavior.