First let me say I agree with you 100%. Let me explain what happened in the design process.
Initially, Ray built the UI and during that time a very basic HTML form was used without Javascript to send the values. Well, the way forms work for a checkbox is an unchecked box will simply not be sent. This makes sense in the setting of the web however this was interpreted as being unchecked by the firmware because it only expected modification from the UI (not via an API).
This limitation had been carried forward for the simple fact of keeping things backwards compatible. However, this can be changed and we will reopen the discussion to change this moving forward.
In regard to the incorrect example, you are right and we will update the documentation to reflect that.
For the rain sensor type effecting the rain sensor flag itself, this shouldn’t happen. I am going to look into this and get back with you.
Thanks for the information!