I opened one with Kasikorn in Big C extra last year. No insurance was demanded either. I went there after telling Bangkok Bank to do one for insisting on insurance
if she's divorced and believes in the sin sod "tradition " her parents will have already "sold" her once. They don't get paid twice for her. I knew about sin sod before I got married 17 years ago but the wife said no. She doesn't believe in it
I went for my stamp today, which was due today. There was absolutely no waiting to get in. I was in and out with my new stamp within 5 minutes. If the op lives quite close and it's no hassle to get there, I'd give it a try. The Immi officer will see the date and hopefully understand. Otherwise he'll be going after the due date, coupled with it being the first day back after an extended weekend. Our Immigration office is packed and large queues after weekends and particularly extended weekends.