Mining address will be posted publicly before Wednesday. This will allow transparent monitoring of the hashing rate and block generation.
So no, they do not have to any time on Thursday.
Once again, they set the deadline, so they must hit it.
Ah, missed that. That makes even more sense - the date they'll give their address is the same as the date they'll pay dividends.
In that case, then you'd go by the end of Tuesday, which is still over a day away. And if you say it has to be before it's Wednesday
anywhere in the world, then you would have to go by 10:00 AM UTC on Tuesday, which is actually earlier then the above countdown clock.
That clock is just a completely random point in time, with no real meaning.