It is safe to use a dolly or sliding stand to move a heavy fridge as long as it is done carefully and with the right equipment. This equipment includes the right sized dolly or stand and strong rope.
Begin by measuring the fridge and any door openings or passageways that it has to be moved through. Check that the dolly or sliding stand used is big and strong enough to cope with the size and weight of the fridge. Once the fridge is on the sliding stand or dolly, it needs to be tied down to ensure it doesn't move or fall. The rope should also be used to ensure that the doors are kept closed.