No there not, mines 4 1/2 and still puts things in his mouth and even an older child can choke on things. 3 is a guideline only.

But your his dad, your entitled to choose what he can/can't do when he's in your care, so as long as your sure he's safe with them then no reason to stop. If he's taking them home with him let mum know he's got them so she's aware he's got a potential hazard on him.