REI cannot change his policy, but they can change his employment.

 Keep in mind that REI and Geocaching have a partnership, so if he is doing things to harm geocaching and he works at REI, I am sure some lawyer can prove how he is breaking the agreement and a law suit could follow.

http://www.geocaching.com/about/buying.aspx

Gear up with REI and Geocaching.com
Geocaching.com has partnered with REI to help you gear up for your next outdoor adventure! Getting started with geocaching? Visit REI.com for GPS Receivers from Garmin and Magellan.

 As such I believe if his managers were informed of his actions and statements to customers, things might change.

I have never yet been in an REI store and really have no intention to start with all the comments I hear from those up north.

On 7/6/06, AZcachemeister <azcachemeister@getnet.com> wrote:
I would also talk with their manager. REI does support geocaching. So, 
this is a rogue response on the employee's part. Not nice.
This person was expressing their personal opinion, not REI policy.
I doubt we (or REI) can change his opinion, but he needs to stop spreading his negative eco-terrorist propaganda at work