seems you don't know. The 20k in cash is a requirement and once out of 100 times i have been asked to show it, same i had to show proof of paid Hotel once out of 100 times.
why should i have 500€ in cash with me, except for showing it to the IO officer? Thailand isn't really a country dealing with cash. I'm used to scan everywhere.
Now there's a Pittbull sitting in a box and doing a pre-check of your docs. He doesn't help, he just makes problems. My lady had to book a return flight, even she lives only 5 minutes from the land border. Asking for the supervisor you only get a "nope".