When I installed my floor this spring (about 31 ft. across) I pulled the baseboard off the wall, laid the floor to within a quarter to one half inch of the walls, then reinstalled the baseboard to cover that gap.
I was prepared to install 1/2" quarter-round or base shoe molding over that, but it hasn't been necessary. The only way you can tell the floor expands is that with direct afternoon sun coming in the doors, the tiles will buckle slightly between two parked cars. But after the sun works its way a bit further in, it lies down again.