Mario Party: Island Tour was released in Japan four months after its North American release. During this time, adjustments were made to the box art: some characters were slightly repositioned, and Rosalina was erased.
Headcanon that they actually do sell Eraserhead merchandise, even though Aizawa isn’t all too happy about it. But underground hero or not, he has gathered at least a little fanbase, and there are being toy googles looking like his or scarfs similar to his “weapon” being sold.
Aizawa may or may not come to terms with that merchandise a little bit more when one day, he and his class are going shopping and when he turns around - having let the kids out of his sight only for a few seconds - he is greeted with the sight of twenty children wearing yellow Eraserhead-goggles and scarfs and posing, reciting things like “No good hero is a one trick phony” or “Logical ruse, guys!”
Aizawa nearly freaking loses it, very uncharacteristically for him, when he gets to witness the kids putting one pair of goggles on Toshinori’s head and the retired hero merrily joining in on their “cosplay”.
He does take pictures of those clowns pretending to be him, though all the while swearing that Mic will not get to see those.