In all my time instructing on the PA28, I have neither taught nor found it necessary to apply carb heat on a powered approach. As CFI points out, the PA28 POH specifically states that the carb heat should not be applied unless there is an indication of carb icing and I seem to recall that the Lycoming manual for the O-320 included a similar caveat. Certainly, the (CAA approved) checklist that I have in front of me makes no mention of carb heat in the circuit. Clearly, there is a requirement for carb heat in the case of the glide approach but, whether conducting a go-around or a touch and go from such an approach, it is difficult to imagine a situation so dire that there would not be time to select it to cold before applying power.
Since the original question related specifically to the PA28, the different requirements of the C152, or any other aircraft, are not relevant. Any aircraft should be operated in accordance with the relevant manufacturer's handbook rather than opinion, habit or urban myth. Insurance companies just love to find reasons not to pay out.