Group Liability Waivers: Is it worth saving the paper?

There has been a bit of gap in time between now and my last post because I have been researching different angles of a liability waiver question that I was asked last week.

Question: Can two different adult riders sign on a single liability release form?
Facts: a trainer and her adult student go to try a horse for sale.  Both want to ride the horse, and both sign their names on the bottom of a single liability release form.

My first reaction was, why not? The purpose of a waiver or release is to alert a participant of the potential dangers of the activity, and to have them sign and accept that in consideration for the right to participate in the activity, the participant will not hold the facility/ activity sponsor liable for harm that occurs.  Why not save paper and have each rider sign his signature to a group waiver?

But then I thought of common practices- we typically each sign our own releases for risky activities, such as for sky diving, zip lining, etc.
Why would that be?  And would it render a liability waiver void to have more than one signature?  I had numerous theories as to why a waiver may or may not be voided as a result of multiple signatures, and went to one of my favorite sources to find a little clarification.

An unexpected dismount: is your liability waiver up to date?

But first, some background information on liability waivers or releases..........

Liability waivers can often bar a lawsuit if they are enforced, but we also read many cases of a court deciding that the liability waiver should be void in whole or in part.  
Some of the factors that a court considers in its decision to uphold the waiver or not are:
1. Time: did the participant have enough time to read the waiver so that the participant's waiver was "knowing and voluntary?"
2. Bargaining Power of the parties: does one party have an "upper hand" over the other party, or a greater amount of persuasion or power?
3. Clarity: is the language of the waiver, and the dangers being waived sufficiently clear, or are they ambiguous?

There are of course a number of additional factors that are used: whether a minor is involved, whether the waiver breaches public policy, and whether the harm arose from a contemplated danger of the activity.

My theory was that a liability waiver signed by multiple, unrelated, adult parties could be valid, but it may also be attacked for ambiguity of who exactly are the parties to the waiver, and for violation of the "knowing and voluntary" requirement.  For example, if a trainer were to sign the waiver, and the trainer's student signed on the following line, the student may claim that she was "just doing what the trainer did," and as the amateur student, relied on the trainer having read the release and did not herself read it.

However, group waivers are often used; as Dr. Doyice Cotten of pointed out, group waivers in which multiple parties sign are often used for health club sign-in sheets, and could be used for group trail rides.

Group waivers are not really advisable, though; as one article posted to noted:

"Gang or group style signatures where all participants sign underneath a single document are frowned upon by the courts. Remember, these waiver/release documents are contracts and they need to be treated with the seriousness of a contract. You need to be able to demonstrate that the participants who are signing these contracts understand them and are signing them voluntarily. So, if a line forms at your event where parents/players are waiting to sign, the parents/players in the front of the line may feel rushed and they might not understand the rights that they are giving up."

My rebuttal would of course be that having just a trainer and a student sign, merely two people, would not create the "rushed line-up" effect.

The bottom line is that a group waiver, or a liability release signed by both a trainer and the trainer's student, would not be per se void, and a well-written liability release could be effective for group waivers at a riding facility, but as a sweeping generalization, it likely wouldn't be as strong as an individual waiver.  

Have you ever signed a "group waiver" as opposed to individualized waivers?  Perhaps on a group trail ride on vacation?  Or for a team sport?

Many thanks to Dr. Doyice Cotten for the insight and feedback; you can find his book on sport liability releases and waivers here.