Part of an invitation to an imbiber

• Invitation advisory, or a homophonic hint to the starred answers' starts
• Quartet often near RSVP
• Setup provider's abbr
• Inits. on an invitation
• Caveat on a cheapskate's BBQ invite
• Abbr. often near "R.S.V.P."
• Informal invitation letters

Wikipedia Word definitions in Wikipedia
BYOB or BYO is an initialism meant to stand for "bring your own booze", "bring your own bottle", "bring your own beer" or "bring your own beverage". BYOB is often placed on an invitation to indicate that the host will not be providing alcohol and that guests ...