Disqualification Substitutes ...

[bob jenkins]

If you pay almost any attention at all, you will know (a) when the player commits his fifth foul and, (b) whether the sub reports before or after the foul.

A sub almost immediately after the foul is committed is more likely to be for that player.

And, even if a sub is already there, most of the time it's only one.

But, yes, you need to read the situation.