If someone has an ADR at the Boardwalk or Yacht Club, drives and parks there, then decides to go into Epcot afterwards, I can't see how it's a problem?
Sure, the gateway is a perk of the guests staying at the Boardwalk/YC, but it's also there for anyone who knows about it to use.
That said - I also like your solution... I forget about the pathway to HS or using the boats from that location (even tho I just did it in FEB!!).