If you didn't actually mess the place up or have anything broken or stolen, I'm not sure how it was disrespectful. Unless your aunt and uncle explicitly told you not to invite anyone over I'm not sure how you were in the wrong. I used to do that sort of thing all the time when my parents went on vacation, and they didn't really mind because they knew I wouldn't be doing anything stupid.
I mean you're not going to have friends over there to drink and hang out when they're home because you don't want to be loud and disturb them during the night, but if they're gone and your guests respect the house, I'm not sure I see what the problem is.
But again, if it was implied that you shouldn't invite people to their house then yeah, you ****ed up.
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