GMorrison
Thats exactly right, and there'll be no problem with reenactments going on. Heck, first Fourth of July parade I went to back in the 90's in the town where I used to live, big contingent of WW2 vehicles and uniformed folks from the era. Including a bunch of SS Waffen guys in camo. Not to my taste and I never went back, but their rights to do so.
One fact you may not be aware of is that re-enactors begin with one impression but add an alternate impression as money and resources permit.
Had the event been scheduled for more that one day, you most likely would have seen many of those very same Waffen SS guys dressed up later as American, British or Russian.
I knew a guy of Japanese ancestry who showed up at an event dressed up as Japanese infantry as a secondary impression;his primary impression was American ETO.
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One additional comment:
As I recall, during the time frame of the 1970s through the 1990s and, perhaps later, the only source of GI WWII rough out boots for re-enactors was - you guessed it- WWII GI rough out boots.
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If other veterans did what my father did, they would have used their boots as work boots.
Guess what? The supply of GI rough out boots was , IIRC, restricted by the 1980s to a very few near child sizes.
I know this because I was trying to collect enough gear to do a GI impression.
Did those Waffen SS guys wear "jack boots" .
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If so, they might have been surplus East German boots or if short boots were used then it was possible to use modern American boots ( no toe cap) as a substitute.
Perhaps those guys in German uniform were unable to assemble a GI uniform.
Please don't judge 'em just on that one event.