I don't consider it GAS when the gear has a specific purpose and actually gets used, I do consider it GAS when someone has multiple cameras/lenses which are near enough the same just sat on a shelf collecting dust.
This is a view that probably won't be terribly popular here, but if you've got a camera that's not getting used or is unlikely to get used that has no sentimental attachment, why not just sell it/donate it?
GAS isn't about having a few cameras, it's more about the buying of gear you don't need or won't use...
Canon A-1 - On Loan to @
PMN .
Fuji GW690 - On loan to PMN from August to March.
Fujica STX-1 - Donated to @
Andysnap Jr.
RB67 - On Loan to PMN for a few months last year.
I'd rather someone made use of my gear than it be sat around doing nothing.
tl;dr
If you use your gear, it's not GAS.