Well - that's where attendance comments come in. The idea is that you can set a small comment for each game - and your coach/manager will see that comment when they look at who's coming or not coming. Note that everyone in the team can see the comment - in the same way that they can see if you're coming or not coming.
Adding a comment
To add a comment - look for the little icon new the coming / not coming icon for the game. For example - if I wanted to add a comment for my son 'Little Coach' on a game - I'm looking for the little blue icon below on the right.
You'll then get the ability to add your comment to your attendance status. Make it small it - it's not an essay!
What the Coach / Manager Will See
In the screen shot above - the coach / manager will see the comment listed against your entry. In this case - it's pretty clear that you're coming - but might be a little late.
Note that the attendance comments are visible across the platform - mobile and web - and are visible to the entire team.