Yes, you can not use an EAP version (except EAP6.1.0ALPHA) in a environment similar to production, this include a productional test environment like UAT or pre-production tests.
You need to have a subscription for these installations.
The zero-dollar subscripion is for development purpose only.
Are you able to point out which part of the EULA covers "production environments" and the requirement for subscription you are referring to?
I was of the understanding that EAP6.2 is distributed under the LGPL and that the EULA grants license to "run, copy, modify, and redistribute" EAP6.2 ?
There ware numerous threads on this topic already just asking about "EAP6.1" same rules apply.
Short answer is, no you cannot use it in production without proper subscription.
For long answer search around forums.