The worries expressed are indeed widespread and common.
It is important that efforts continue to be made to make people aware that a public telephone network is just that. It is sadly very common for various types of organisation to make Silent Calls (including at one time, but perhaps no longer, BT and HMRC). There will always be those who operate at the fringes of regulation and beyond, however all those with any sort of reputation must recognise, or be compelled to do so if they do not, that Silent Calls, at any level, are unacceptable.
By coincidence, I note that Ofcom has just published an
updated guide on the topic of Silent Calls. Whilst the essence of the policy that Ofcom follows should be correct, there is a quite improper emphasis on the fact that Ofcom finds only a limited proportion of "abandoned" calls to be acceptable. It is also implied that Ofcom has the statutory authority to impose "rules" on users of diallers in general, which is untrue.
If every "abandoned" call were covered by a properly worded Informative Message, then there would be no "Silent" Calls. This measure if far from being just one of a number of "safeguards", although that is how Ofcom treats it.
Ofcom's so-called "enforcement" approach (followed on the inaccurate assumption that there are "rules" in force) is focused on lengthy investigations that may result in financial penalties for a very small number of offenders, rather than a proper use of the powers available to it to simply stop anyone found making Silent Calls from continuing the practice.
The BIS department will shortly be consulting on a quite unnecessary increase to the maximum level of fine available to Ofcom. I will be strongly opposing this measure and have already urged the BIS to get Ofcom to use its powers properly to stop Silent Calls being made, rather than penalising a selected number of offenders. (Some of those already penalised have not been found to have made a single Silent Call, just too many abandoned calls covered by the Informative Message - a quite different issue.)