This is more of a curiosity question as I'm not sure many people would encounter the need for this, but if someone has I'd love to hear of potential solutions.
This KB https://help.k2.com/kb002089 discusses how to set AutoComplete Strict Validation to false, but it does it at the site level, which I think it's a little too overarching. I feel it should be available at the control level. Has anyone tried to allow non-existing values to be input in an AutoComplete control without having to disable it site-wide?
I disable it site-wide, and then for controls that shouldn't allow it I write some rules to clear out the value if it is invalid on change. Not great, but it works.