RE: When people ask you...
I'm also one not to complain or who finds it hard to say No, but with my Heli's, if someone comes up and asks for a fly..... NO WAY!!!
Regarding my 450 class Heli - those rotor blades are spinning at upto 3000rpm, therefore if they come into contact with anyone or anything (pets etc), can cause serious injury! Especially flying in a field, where there may be families walking or people walking their dogs.....
Also as said, this Hobby is not cheap, the Helicopters are expensive to build and repair, therefore with the chances of them trashing the Heli in the first 30 seconds being very high, it really is a no brainer - the person probably has never flown an R/C Helicopter before, let alone held an advanced controller!
For my 450 Heli - it would be a stern NO SORRY! However for the tame and cheap to repair Blade CX2, i *might* consider giving them a quick fly.