Can you let your caravan out whilst it's on a cara

Hello, new to caravaning, we have our caravan stored for a year on one site, we then pay  for a pitch and bring it out of storage and pop on a pitch. We aren't touring in it because of the length of the caravan, saving for C1 vehicle, but I was wondering about either

a) letting it out to people we know well and trust.

b) letting relatives stay in it when they come and visit us.

Questions are, can you let someone else stay in your van on a holiday or do they have to be caravan club members? More of a question of can people stay rather than a money making exercise. For instance, one set of friends are letting us borrow their canal boat for a week as a thank you and I was wanting to return the favour.

Thanks for any info in advance