Just wanted to share my experience. I went this morning to the "temporary" K Counter located in Muang Thong Thani.
My intention was to get a 30 days extension. I know I do not need an extension since the blanket immunity is implemented BUT I was under the impression that nothing would guarantee that I would be able to get an extension after the amnesty is waived, and also I will then be 2 weeks behind the end of my 30 days exemption entry stamp.
That's a thought that Tod also shared (he said something like 'I only trust the stamps on my passport', and I agree 100% with him).
However, upon arrival at the gates I was greeted by a very professional staff who asked if I was aware of the blanket amnesty. After that, he told me that I didn't need to do any extension yet and I could wait for the amnesty to be waived. He also told me I was free to get inside the building to ask for a 30 days extension if I wanted to. He assured me that I could get an extension after the amnesty is waived and I decided to trust him.