We (me and hubby) arrived in Thailand in March, on visa exempt and have had one 30 day extension. Yesterday we went to Chiang Mai Immigration at Promenada. Here's what happened. We were applying for the 30 day extension with our NZ Embassy letter. This is because NZ have put restrictions on flights. Firstly, we were told we should wait until mid September, to see if there's another Govt announcement. The staff were helpful, but then said that our Embassy letter should have been dated after 23rd July. Unfortunately our letter was dated 16th July, we were being proactive when the announcement first came out. The nice lady there also said that if we can show them a flight booking for October they will grant us our extension. But at the same time telling us that Head Office have to make the decision. So, the moral of this story is, your Embassy letter is NOT a guarantee to getting an extension.
TLDR : Answer Summary
The user, along with their spouse, shared their experience applying for a 30-day visa extension at Chiang Mai Immigration. They had a letter from the New Zealand Embassy citing flight restrictions, but were informed that the letter needed to be dated after July 23rd, and they would need to show a flight booking for October to be granted the extension. It was emphasized that having the embassy letter did not guarantee an extension; final decisions were to be made by the Head Office. Several comments provided tips and insights on dealing with similar situations, including the possibility of getting a new letter from the embassy and the challenges of securing flights back home.