Every one of you has slightly missed the point I was trying to make, so I'll try again. It's a simple point - Time and place.
If you're at the event, then yes, remain in uniform, be proud, and live in the moment preferably as a unit. Take refreshments as a unit - set up a unit canteen - hell, use it as a fund-raising device for the unit; sell period refreshments, or if that is not palatable, put modern soft drinks, etc., into period containers. I think that is acceptable. You don't need to torture people by expecting them to live on German black bread, sausage and warm water out of aluminum containers for two days straight - not only would it be a disincentive to participating, but it would actually be hazardous to their health. If you don't have an interest in the living history aspects of the hobby, then don't hang around ruining it for those that do; leave the area before changing out of uniform.
I certainly wasn't advocating stripping out of uniform WHILE AT THE EVENT. I meant that if you're going to leave the confines of the event area, then that is the time to get all the way out of uniform. It's not a costume. Modern militaries have regulations about being seen in public in uniform - you're not allowed to wear field dress to the local mall or bar after being in the field for an exercise, for example, all covered in mud and dirt - you go home and strip out of your grungy clothes first. So why should pretend soldiers presume that they should be seen that way? Pat says "we all are far better". Sure, then prove it. Have the pride and discipline to know when to wear the uniform, and when not to. Again - it's a uniform, not a costume.