If they go directly to Louisville, and want to stay at the Galt House, they will have to pay for the additional nights that they stay.  The rates you already saw: $119/night plus tax for deluxe room, and $129/night for executive suite.  Please note that when the conference begins on Aug 9, the room assignment will change.  They should only book and pay for the additional nights.

(1) Use the following link to book your hotel: https://aws.passkey.com/go/ubf2018

(2) Call the hotel directly, and mention that you are reserving for the “2018 International Summer Bible Conference” to get the discounted rate.

You can also find additional information here:http://hiskingdom2018.org/faqs/#early-arrival