The reason for Thursday games could be ;
1) Long weekend no games
2) Give the boys a rest on the Sat 17th June before GPS games etc.
No the worst idea.
No one is resting on the 17th of June. Full list of GPS round 6 matches are on that Saturday, then the GPS games on the Tuesday 20th just after.
Normally there would be no game at all on the long weekend, however the real reason for squeezing this round in on a Thurs afternoon (only 1st & 2nd XV rugby, no other sports or age groups) was that it was necessary to get in 6 games in Term 2 to allow for a 10 round home and away comp. The AAGPS sports calendar only allows for the first 4 Saturday's in term 3 for winter sports competition before switching to athletics for the rest of the term.
Maybe in future the calendar might allow for term 2 to be two trials and 5 comp games (with the June long weekend free), then term 3 with 5 comp games to end the season before Athletics.