The thing about making social plans is that they are always subject to change, especially if they involve a lot of people. Being a good host or even just a good friend is a matter of adapting to this, within reason. This is especially true if you're expecting guests: unless somebody does something awful, shouldn't you try to give everybody coming to your home the same treatment?
This isn't what one woman experienced when she met her now ex-boyfriend's friends for the first time. He invited her as a plus one for a pre drinks and barbeque, but when they got there the hosts informed them that despite there being twelve guests, they had only cooked for eight. They ate without the four extra guests and then told them to have the leftovers. The internet agreed with the woman that this was strange behavior. If you don't want to be hospitable, don't let that many people come over.
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