After chatting with Goldy, I have some thoughts on stall counts.
Stall counts seem to be contested more often than any other call (that's my rough impression).
It is hard to make a judgment on the timing of a spoken word relative to an action, particularly if your focus is on other things. So mortal humans disagree on whether the disc was released or not. (It is easier to judge whether a foot moved, or landed on a line, or whether you felt contact).
Now this process is only aggravated if you say "...8...9...10 stall!". The thrower has to judge the timing of the release relative to the word "10". But you have uttered a word straight after that. An excited word at that!
One way to help this is to not say "stall" straight away. Leave the "10" hanging in the air for all to judge.
And then say "I'm calling stall" a couple of seconds later. This also gives you more time to judge whether it is a stall or not, without the accusatory blurting of "Stall!" mixed into the timing.