[AZ-AlphaXi]

Here's what the MOI (aka green book) says about snap bids

8. Snap bidding is allowed only for those chapters that did not match to quota in the bid-matching process. Women who participated in at least the first round of recruitment are eligible for snap bidding. Snap bids can be extended,
coordinated through the Panhellenic, prior to the start of Bid Day activities or when bids are distributed.
9. If the preferential bidding system is used, women who indicate an intentional single preference and do not receive an invitation to membership are eligible for snap bidding and COB, but they are not eligible to be a quota addition.