Okay, so I actually found the place in the software license where it stated the only thing I could find that might be similar;
"You agree not to otherwise reproduce, copy, modify, decompile, disassemble, reverse engineer or create derivative works of any portion of the Application and Data, and may not transfer or distribute it in any form, for any purpose, except to the extent permitted by mandatory laws."
The application refers to the interface, garmin software (the gps itself), and the map data. The map data is actually third-party information that is licensed, not sold, to Garmin. So I think as long as you aren't trying to reverse engineer those copyrighted maps/ interfaces and/or trying to sell or redistribute them, you are fine. I have gotten numerous accounts of confirmation from Garmin that third-party maps are allowed. I even found an official article instructing you how to properly download third-party maps -- which requires putting those maps into the .img format in order to enable/disable them.
So unless I've missed something, I think we're okay. Any outside comments are appreciated.