Miss Manners: Party host asks for donations for expenses after the event

Dear Miss Manners: In January, I had the pleasure of attending two holiday parties. Both events were potlucks, to which I gladly contributed dishes. The hosts provided beverages like water, tea and coffee. The parties were well-attended, and everyone seemed to enjoy themselves.

However, a few days after each gathering, I received a message from the hosts. They mentioned the amount they had spent on the party and requested a $10-$30 donation from the guests, providing their financial app details for this purpose. This approach struck me as more akin to a fundraiser than a social gathering among friends. Is this a standard practice in modern times? Is it now customary for hosts to ask for post-event monetary contributions to cover their expenses? I want to ensure I am up to date with current social etiquette.