i usually look for sites at the local parks where they would work for one camper pulled in and one backed in. That way awnings are facing each other and we have our own large space.
I've seen this on a number of occasions. Makes a lot of sense to do it this way. Units also serve as a sound barrier.
Instead of getting all ruffled feathers and resorting to juvenile behavior, why not just politely ask the offender to keep their stuff on their side? I've had to do this a few times and each time it's been met with "oh, I'm sorry-we'll move it" with no argument. If it continues then go to cg management and ask them to stop by and "remind" them. Bad behavior by one doesn't justify bad behavior by another. While I do find some of the responses amusing and most likely harmless minding one's OWN manners should be paramount.