It is possible to define a special number format for CAS numbers, and even validate the check digit. Here is an old Stack Overflow post that explains how: stackoverflow.com/questions/51...

Want a moral? Lawlessness is not just an exciting chance to make big money. Autocrats won’t always be on your side. You are better off under the boring, confining rule of law, because once it’s been demolished you are not in control of anything. Perhaps no one is. Especially not you. (8/8)

“What is happening is that they’re basically blocking the process, just by an administrative, legal means, rather than by ordering staff not to make grants,” said Jeremy Berg, who directed the National Institute of General Medical Sciences at the N.I.H. for eight years... 2/n

...Portions of ... meetings that were once open ...have now been closed, the guidance said. As a result, review panels were being canceled en masse because of a failure to announce them to... the public who were barred from attending them anyway. “It’s a Kafkaesque thing going on,” Dr. Berg said.

Read this, again, this morning: bigthink.com/the-present/...