He did not mean that. He meant that when the DTV was launched many were saying getting an extension at Immigration Office for another 180 days would be easy - that has proved to be false. Yes, it is easy to do a border bounce for 180 days
Currently for entry and another 180 stamp there is no need to show ongoing courses. If you wish to extend in country at an Immigration Office you will need to show this.
Not blacklisted as you woukd not be allowed in. Definitely looks like you have a note on your record though. Pal had similar coming up and down from Singapore where he was PR. Told to get a visa next time, not Visa Exempt.