@Anthony *******
Yes, to apply for short extension between August 1 and Sept 26, to stay after Sept. 26. From article "However, if they do not obtain extensions and are still in the country after Sept 26, they would face legal action and be blacklisted." So overstay under this new proposed grace period if denied extension would occur after Sept. 26. Ubon Joe in ThaivisaNews said he believes the blacklist will be applied as normally, so at 90 days when leaving the country or if caught when on overstay in country.
People also do have options of changing short term entries like visa exempt and tourist visas (both of which are classed as tourist visas really) to longer term visas (Marriage, edu and retirement, work permit) in country, mostly by using agents.
We will know all the details by tomorrow or the end of this week.