Thanks a lot for really throughout description.
I did not even think the regexps would be part of the "problem" of mine. Now as you mentioned them, it is really natural reason why so many VM match in my original filter. Of course it is still odd that the IP address is skipped in case there are more hashes in filter and not skipped if it is the only one. Thats more than a bit confusing at least for a newbie who tries to learn by doing 
.
But lesson learned; If I want to search some VMs by IP address or any other infromation that is only available if VMware tools are installed, I should first check that the tools are OK.
Also the second question is clear now as you described the design philosophy behind the current behavior.