In reply to Daniel Duerden:
For official DofE guidance on the use of me bile phones and radios, consult chapter 9 of the 13th edition of the Expedition Guide.
Essentially, it recommends that mobile phones and radios should be used for emergency use only, but, reading between the lines, there seems to be some acceptance that some groups will want to stretch the definition of 'emergency'.
It is also instructive to remember that there is no 'one DofE', and that award programmes are tailored to the capabilities of individual participants.
For those parents arguing that they wouldn't want their children to be carrying communications equipment, I'll ask if they would be so sanguine if their child happened to die for the lack of what is everyday emergency equipment. Whilst rare, there are incidents where conventional emergency procedures would not bring help fast enough.
Most DofE supervisors are volunteers, and, for non-adult participants, are responsible for the safety of participants. As such, they should be given the right to decide what emergency measures are put in place. If you don't like it, don't place that responsibility in their hands.
The group I help with uses GPS trackers and phones. The phones are generally reserved for emergency use, but are turned on, and we sometime use them to ease supervision, This doesn't mean that we are sat in a van stuffing our faces with buns; we're out in the field tracking multiple groups. Everyone is made aware that both tracker and phone may not work, so conventional procedures are also taught, and we observe them and meet them in the field. We don't shadow them, even at bronze practice. Shadowing teams from 10m? Blimey, they must have been unobservant, or you're a ninja; ours sometimes spot us hiding behind bushes from 100s of metres away. We don't do gold, but I would expect ours to be making very few navigational errors by that stage; silver assessed in usually uneventful.
As for PMR446 radios, well, they operate at, no surprise, 446MHz, which is essentially line-of-sight, with a range of about 2-5km, depending on conditions and handset.