Maybe a better wording would be :-
"Any smart-alec statement you make really is likely to end up being repeated in court by a very smug prosecutor and nobody will find it the least bit charming.
You will want to die of embarrassment, your brief will want to strangle you, and the magistrates may have a collective coughing fit."
For example, I bet the young man I saw recently for drug-impaired driving really regrets telling the policeman "I drive better on cannabis".
There's not much a defence lawyer can do with that - in a nice snappy sentence he showed himself to be without remorse and a regular offender. Even "it's a fair cop, guv - you got me bang to rights" would have been better.
Incidentally, I doubt anybody does anything better on cannabis. Least of all something requiring reflexes and concentration like driving. Or talking to the police.