I've never been asked to show this. Not once in 3.5 years with numerous visas and trips in and out. That said, I typically have it on hand just in case.
I didn't apply for it because we're a family of three and this thread had me concerned that METV was harder to get as a family. Didn't want to risk it or lose the cash.
I would not use my family as a reason for requiring METV. It's my personal incentive but not what I would present to the Thai embassy. My circumstance is unique. Not sure I'm going to try for it or not.
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