It could be that she screams for attention when ppl are there because she doesn’t get it when they are not there and she doesn’t have leverage to get their attention.
We do not spank Loren. We rely on time outs for bad behavior and lots of praise for good behavior. It works. Teaching children to behave is not something you can do for a while and then it is done. After a while just a frown or a smile can do as much as time outs or effusive praise.
The screaming when out to play is fairly normal, it can be extinguished like any other behavior, if the parents want to.
I really don’t know how parents teach children to behave properly in public or in front of company. I can’t see that we have done anything special towards that. We expect Loren to behave a certain way. When she doesn’t, we explain why she get a time out. Unless it is a tantrum. Tantrums get time outs immediately no explanation. Time outs in public are not easy, we just cut the trip short. I think that has happened twice. When company is over she tends to put away her least attractive behavior (screaming at the top of her lungs just to have fun–we are working hard to stop that one) and brings out the cutest behaviors. She doesn’t demand to always be the center of attention.
What you can do. If she is your guest, make sure that her basic needs are filled. I try to serve all my guests beverages promptly. I also tend to have at least a little something out to eat. By making sure she has these things you deprive her of a chance to demand attention. Standing on the furniture with shoes, explain to her that is not something that is done at your house. Explain this to her parents. It should be interesting to see their response. Do jump to remove breakables from her grasp before she dashes them to the ground with the explaination that she might get hurt. Do not tell them how to control their child unless they ask. It will not be appreciated. If they continue to allow her to behave in a way that you do not allow at your house, don’t invite them back inside for quite a while.
If you want to help her, you can invite just her over for a nice visit, have tea or something she would like and cut the visit short if she misbehaves. That too can inspire better behavior.