I'll stand youngsters making mistakes all day long, it's part of learning, what i will not stand is cowardice. I don't mean a terrier coming away as it can't find once it's moved, we all know that look a shitbag gives you when it comes away after making contact, if it goes back again and still doesn't stay and the fox is still in the same place then theres no excuse for it. If a youngster looses one but goes back and can't work it out but is still as keen as mustard then put it down to experience, in my book as long as they've got the drive and want then give them time to learn their game.