TRUE, but, one would never see it, as the fan clogs inside by the actual fan intake. To circumvent this problem I installed a course filter as the grill intake is too large to stop anything except a kleenex tissue. Unless taking the whole rear end and right panel and about 20 bolts and other assorted hardware turns you on. :cheer2:
I did similar, put a filter designed for use inside a vacuum cleaner behind the grill of the traction battery fan duct. Had a look at it recently: it had just a few accumulated specks of this and that. I also tore down to the battery, and took off the intake duct. It was a bit of a fight due to very stubborn fasteners on the carpetted flooring. Our fan looked pristine so far, car is only 7~ months on the road. I removed the stubborn fasteners from the floor panel before putting things back together: there are plenty of secondary guide pins on the floor, plus one hex bolt. Just to make it easier for future checks.
Toyota definitely could have designed that area better, that cooling fan is probably totally ignored by most owners. :cheer2: