My guess is that if your grill won't fit in the food storage locker or inside your vehicle, they may cite you for it....imo.
"Enforcement" of the rules is sometimes inconsistent in my personal experience at MG.
ood Storage
Animals are attracted to food and food odors. All food, lawfully taken fish, garbage, and equipment used to cook, serve or store food must be kept sealed in a vehicle, or in a camping unit that is constructed of solid, non-pliable material, or suspended from any NPS designated food hanging device, or secured in any NPS designated storage locker, secured in an Interagency Grizzly Bear Committee (IGBC) approved bear resistant container or secured in a structure or dwelling, at all times, except when these items are being transported, consumed, or prepared for consumption.
Do not burn waste in fire rings or leave litter around your camp.
Garbage must be properly stored at all times. Use bearproof trash cans.
Violation of food storage regulations may result in $75 in fines and fees and/or confiscation of improperly stored items.
I have this one and it fits in the lockers at Many Glacier.
pete