Or C: Follow the tournament format of the date and time and either sign up or don't based on your knowledge when you can or can't play.
Honestly, if you look at any respectable tournament, they have set dates and times for each match. Look at the IEM or ESL for example. They have like all first-rounds at 7:00, then all second-rounds at 7:30, then 8:00 for the next, etc.
If we had to wait for every individual player to play based on THEIR schedule, one tournament would take a week because everyone would be all over the place, especially if they knew it was on their time, there would be no rush for them to play.