Dave Liquorice wrote:
If you make a sound when you pick up the call, then the calling centre
routes the call to a human who you really don't want to talk to.

I don't think that happens. Silent calls are just the call centre kit
dialing calls before there is an operator free to take the call the
moment it is answered (if it is). Having a CCO not talking to someone
costs money.

I must be plagued with different operators than you ;-)

I get a few of these a month, and previously when I have said "hello" an
operator has either responded back, or the line drops immediately. Now I
say nothing and wait for someone to make the first move. They never do,
silence and the line drops ;-)

--
Adrian C