Last night we went to a cocktail reception on a Navy Ship. There must of have been 300 people there. There were about 30 seats (without a table). 10 of which had reserve signs. I never saw anyone in any of the seats. There were a lot of cocktail tables and people just hung out there.
That is pretty normal for cocktail receptions I've attended. I've never thought twice about it, but everyone here thinks it a major problem.
What differentiates an average host and a great host is anticipating unexpressed needs and wants of their guests. Just because the want/need is not expressed, doesn't mean it wouldn't be appreciated.