Just to clarify:
{(x.1234|?):},{ph} would not block anonymous call, by design. This syntax is not meaningful; you are right about that. If it blocks anonymous, that would be a bug. We will check on that again.
{(x.1234)|?:},{ph) is the correct syntax to block anonymous call (and any number ends in 1234).
Just beware that inside parenthesis () is a digit map and special symbols will take on different meaning.
x?@. are some examples.