Résumé en français : des sociétés n'hésitent pas à  passer des appels "silencieux" pour mettre à jour ou pour compléter leurs bases de données.

Have you ever been at home in the middle of the day and picked up the phone and there was no one on the other end?
You may have been the victim of “Silent Calls.”
This is when a company phones you, using a call centre with an automated dialling service, and they do not have the staff to take your call.
There is no one on the other end to identify themselves and the caller is left, especially old, frail, and vulnerable people, feeling harassed and victimised.
Worse, still, a company may even be checking to see if you are in during the day, only to target you later with a flood of sales calls. Or even sell your number to other agencies.
In the UK, telecommunications regulator Ofcom this week fined credit card operator Barclaycard £50,000 for making “substantially more” than the 16,000 calls for which building society Abbey National was fined in a previous case. Ofcom chief executive said; “taken as a whole this is the most serious case of persistent misuse of making silent and abandoned calls that Ofcom has ever investigated.”
In 2006, Ofcom ruled that calls that did not reach a consumer must carry a short message identifying the company and should not account for more than 3 per cent of live calls in 24 hours.
A Barclaycard spokesman said,” We recognise that all calls should be made in the right way and we accept that our process was inadequate. As a result we offer a full apology for any inconvenience and distress that these calls caused.”