Going entirely by my memory.. i believe the tps guard first showed up on the sx based models, after some reports of the tps being damaged by rocks, etc.. On those models the tps was exposed, not hidden behind the gas tank. FF to today where now several models use the same tps, even though the tps is hidden behind a frame brace, and in the case of the exc also behind the gas tank. So it's plausible that they're just using the same part as-is across models to make manufacturing and parts management easier. However, they didn't have to make it such a bugger to remove the guard, so it's also plausible that they're trying to discourage fiddling with it to appease the epa. I could never encourage removing safety equipment, but it does seem like the tps would be reasonably protected even without the guard, given its location behind the frame brace and gas tank.