I found this great article/post on an industry discussion board and thought I'd share it with you all. These are great ideas to get your attendees to book under your contracted room block!
HOW TO ENCOURAGE ATTENDEES TO BOOK WITHIN YOUR ROOM BLOCK
POINT SYSTEM...Offer points to those who book within the hotel room block and give the companies who have the most registrants and "points" preferred exhibit locations and headquarter hotel upgrades/comps
MARKET THE BENEFITS...No full payment required, easy to change reservations, increased networking opportunities, support of your organization and one stop shopping
"NO SOUP FOR YOU"...Don't allow an attendee to register for the meeting without booking a guest room within your hotel room block
MO' MONEY...Charge a higher registration fee or exhibit fees for those who don't stay within the hotel room block
PARTNER...Work with your hotel partners to provide special discounts on local attractions, restaurants and hotel merchandise
SUPPORT...Explain why and how an attendee's choice affects your organization
TWO ROOMS PLEASE...Require that two rooms be purchased within the hotel room block for every 100 net sq ft of exhibit space rented
Hope these work for you and your clients!