I would happily lend an air rifle to a (trusted) friend. But I would satisfy myself that that friend was reliable enough and knew how to properly use and look after an air rifle.

I have had an 'experience' before when a fellow club member, through ignorance/inexperience, used my springer which was on loan, for dry firing..... It wasn't carelessness on her part. Probably on mine as I should have ensured that all these basics were understood before she got the loan.