Letters of invitation?

• Letters on a party invitation indicating that booze won't be provided by the host
• Party invite letters
• Party stipulation, briefly
• Party directive, briefly
• Party rule, for short
• "We're not serving liquor" party invitation notice: Abbr
• "No alcohol provided," briefly
• Letters on a frat party invitation
• "We're not supplying liquor"

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 ...