I have heard this about those intending to try the A380 on a FRA rotation.
Flights to FRA will be sold to A320 capacity only, meaning smooth transition of pax to a regular A320 should the A380 not become available at the last minute. Also flights on the A380 will become known 48 hrs in advance. Some flights will only use the lower deck and some the upper deck, not both on the same flight, for cabin crew training purposes.
If you’re excited – great. If not or you don’t care then I understand too!