So in your post you state that insurance is needed for an OA and ask about it, and then in the comments you state that you have a NON O. Why ask about insurance for an OA if you don't have one??
Should be fine if arriving with more than 6 months and not intending to stay long term (an exiting flight itinerary will help with that) BUT they may question it.
Kevin Mackenzie Not when you have had 2 x tourist visas and been refused a third it won't. They check the visas in the passport, so they don't care if you were out of Thailand for a day or a month ;)