We are having an evening reception, starting at 7:30. Very small afternoon wedding, very large reception.

We are not serving dinner, instead will provide a lot of our favorite appetizers and refreshments (an outlandish list of eclectic items)...

A couple of friends have suggested that the 7:30 start time implies that a sit-down meal will be served. I disagree, but I don't want there to be any confusion or embarrassment for our guests or us when the time comes.

How can the invitation be worded to subtly inform people what to expect?

Btw, the location promotes walking around or sitting in small groups, it is not going to have rows of tables at all.

How about something like this:

Please join us at our casual reception at 7:30 p.m. at such-and-such location for an eclectic array of hors dourves and refreshments.