As I understand the documentation ANDs are implied, so "eventtype=A eventtype=B" is the same as "eventtype=A AND eventtype=B"
Also, if the tag names are the same like in this case it is interpreted as "eventtype=A OR eventtype=B".
So my question is "eventtype" a tag name or not? If I do a search the search results say eventtype is both A and B! I don't understand.
It is AND - which documentation are you referring to?