[bossref]

I was challenged on this issue back in the
early 80s, so I wrote to REFEREEE Magazine.

The response I got was that even though it is not
really a travelling violation, the signal does communicate that a violation for moving had occurred.

I didn't buy the explanation then,
and I still don't agree with it.

Use a signal similar to a 3 seconds violation
by pointing to the spot and moving your arm sideways.
I make sure to verbalize "SPOT VIOLATION".

It is not illegal to move one or both feet
on a throw-in! There is no pivot foot restriction.
How can it possibly be called travelling ?