the examples you have given is streotyping in the extreme.
No, the stereotype is saying all squaddies are trouble, not my examples. But it is no different from saying all single sex groups are trouble. Or all school children are shoplifters. Or all male drivers are more likely to have an accident than female drivers. Clearly on a case by case basis none of these are always true, but the policies are put in place to minimise risk.
The hotel perhaps should have used common sense, but if that's policy then it's policy. It's no different just because he's a soldier, there are thousands of examples of discrimination based on stereotypes.
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FWIW - I respect our armed forces doing a tough job risking their lives, for little money with shite quipment in wars that our governement should never have put them in.
But at the same time it is what they signed up for.