Thats not a black and white Q... I will give you 2 e.g. .. these are factual..
I was judging a Prof mambo comp in the late 70s.. a 6 couple final.. next to me, was a world reknowned coach in Latin... he turned to me and said ( which made laugh ) " Terence, if you see anyone on time, lets mark them 1st. ! "
Second.. this was stated by A. Moore..... a student asked him this Q.. " Mr Moore if I were off time ( it was Cha ) would you mark me ? ".. his response.. " Yes, as long as you stayed on the same beat " .
To mark any competitor over another, one has to take multi things into consideration.It would depend on how often and in what circumstance .
"Off time " was always considered one of the cardinal sins in dance.
Now , obviously if it were W, I would not even consider marking.. I might give a little more latitude if it were QS, Mambo/Salsa .
And, all of this is contingent on the level of the comp. ( Novice.. pre champ etc ).
Judging large rounds is never an easy task, and "catching " someone off time might be an isolated instance .This goes towards explaining why sometimes you see very different marks ( or no marks ) in larger events.. the disparity is usually minimal in Finals .