Seen It Twice

Two Kerrymen were watching a John Wayne film on television. In one scene John Wayne was riding madly towards a cliff.
'I bet you £10 that he falls over the cliff, said one Kerryman to the other.
'Done', said the second.
John Wayne rode straight over the cliff. As the second Kerryman handed over his £10, the first said, 'I feel a bit guilty about this. I've seen the film before'.
'So have I', said the second Kerryman, 'but I didn't think he'd be fool enough to make the same mistake twice".