RD Advice

I am really confused what to do about this one. We are not having a RD technically. Honestly we just can't afford it, plus we aren't having a rehearsal so don't need RD. We would like to have a few friends and relatives, mostly the BP and OOT guests, meet us the night before the wedding in the restaurant in the lobby of the hotel we will be staying at. (We decided on the Melville Marriott.) How would we word invitations to say 'Please join us' without making people think we are paying for their dinner? Or should it be just an oral invitation like 'Come meet us downstairs if you want' ?

Thanks, brides.

Heidi