[Kiran]

regarding a visual indicator: I think it could definitely be useful, especially for newer players, but I don’t think it’s necessary.
In my (tbf limited) experience when playing the visual indicator I go off of is the thrower’s foot inside the playing field and that has worked well so far.

[Rueben Berg]

Thanks for everyone’s comments – this has been shared with the WFDF Rules of Ultimate Sub-Committee.

One of the issues in mandating a ground tap is that would create an avenue for play to stop when a player fails to ground tap, which is not ideal.
I am very open to the idea of suggesting a ground tap is a good way to indicate when the thrower has established a pivot point, likely in the official annotations, but don’t think it should be mandatory.