If that sort of practice is really happening then your first step might be the club - then the CAA.
But for your own sake learn how to assess whether the aircraft is flyable or not. Yes you might expect a club to go a long way towards helping you. But there are any number of mechanical and other issues which can all occur with little warning - from one flight to the other.
If you cannot make a 'go, no go' on your own initiative and knowledge then you should perhaps consider whether flying is a smart recreation?
I'm not trying to be especially smart, but for your own and your passengers health this is a skill you need. There is little more annoying than being stranded somewhere with a 'duff' aircraft - unless it is 'being up there, wishing you were down here'.