"It's their choice," says Federico Bertilotti, of Saracens supporters services.
"They can back their team and get a refund to celebrate a win at Allianz Park, or they can hedge their bets and get the full refund as consolation for a defeat. They can let us know when they call.
"Either way, they'll have a great day out and see their team play for the very first time at Allianz Park.
"We're offering parking near the ground at £10 per car, so there is every reason for Gloucester fans to get on the road and make their way to north London on Sunday."
This offer is only available to people living in a Gloucestershire postcode who book their tickets through the Saracens ticket office at 0203 675 7200.