At the AACE Convention, we had 5 full-time halls, each with the SQROT program running. When couples checked in and received their packet, they were given a tag with a unique number on it. This number was entered for the 'Couple Name' on the computer in each hall. Each hall had a 'rotation manager' who was responsible for the rotation in that hall. When the couple enters a hall and wishes to dance, the couple tells the 'rotation manager', and (s)he makes sure that the couple is active in the rotation. When the couple leaves the hall, the couple tells the 'rotation manager' to remove them from the rotation.
This procedure worked reasonably well. The important thing to emphasize to dancers is that they must sign-in when entering the hall, and sign-out when leaving the hall, if they leave before the end of the session.