Screening Of Speaker Cables

Is it usual or unusual for speaker cables to have screening against RF/EMF?

Most seem to have floating screens so how effective they are is questionable. I suppose a lot depends on the amplifier you are using and it susceptibility to RF entering via the speaker connections.

Some go to great lengths into screening whilst others don’t.
Although my Nordost Speaker cables are fussy about placement to other cables and general dressing, as they have no screening.
May well be system dependent as to needing it.

I’m not convinced screening does much to a speaker cable, either positive or negative, but I’m open to learn if there is real science in it, as apposed to myth & hyperbole.
At the moment I am inclined to think a speaker cable screen is marketed as a plus feature to add perceived value & its price point.