Here is the latest team manual I could find from 2019.
https://www.memphisinmay.org/sites/567/uploaded/files/WCBCC_TeamManual2019_FINALPRINT.pdf
The flooring options are on page 8:
FLOORING AND GROUND COVER
Flooring must allow the grass to breathe. Pallets covered by plywood or any like floor support design, which keeps the flooring off the ground is acceptable. Any surface, which smothers the grass, e.g., tarpaulins, carpet, plywood or plastic drop cloth, may NOT be placed directly upon the ground. Teams are allowed to lay sod, but the sod must remain after the contest. Memphis in May will not supply flooring to teams. Teams must rent or bring their own flooring. Teams may NOT use mulch, hay, straw, sand, or gravel.
It also says that you must get the tent from their recommended vendor on page 5. I assume that’s also who you need to rent the floor from. Unless you want to scrounge up a bunch of pallets and haul them there it sounds like a floor rental may be the way to go if it isn’t too expensive.
TENTS
All team tent rentals must be secured through Mahaffey Tent & Event Rentals, the official and exclusive tent company. No other tent rental companies will be allowed on the property. A violation of this rule will result in a $500 fine, forfeit of any prize money and inability to compete in the World Championship Barbecue Cooking Contest for one year.
Tents must have both a Fire Safety Permit and a Flame-Retardant Certificate in your team’s name. Both must be shown during inspection. If rented, obtain a copy of the Fire Safety Permit and Flame Retardant Certificate from Mahaffey Tent & Event Rentals only. Your tent must also have a flame-retardant certificate, or be tested by the Fire Department at the Avery office or on-site. Cooking rig awnings or covers are also considered tents and must pass inspection and are subject to inspection fees. Permits may be purchased at the Fire Prevention Bureau at 2668 Avery, Memphis, TN 901.320.5418. Inspectors will accept payment by check only. Please note that tents and tent walls will not be installed in winds greater than 20mph.