This is still an issue even with the recent 3.1.3 release. Why was this removed?
"Try togging off the Wrist Detection (available on the Watch app on your iPhone) - then see if the lock is available in Control Center."
This recommendation is unbelievable. Really? In order to have the lock button available, I have to turn off my Wrist Detection? Why? This makes absolutely no sense at all. Many of the users have children, pets, friends and signficant others and would like to be able to play with them, hug them, etc. without having the watch be affected by an accidental tap by someone's head/arm/shoulder/nose/whatever. Please tell me you're going to put this back in on the Control Center, even when Wrist Detection is enabled.