Search for objects with warning/error/invalid data

[naoliv]

(don't know where it actually belongs, so I am reporting it against "Core")

Sometimes I see objects like this in JOSM:

The validator doesn't display anything about it but from what I see, there is always something wrong with those objects:

• tagging a node with a key/value that is only relevant to a way
• using a key/value wrongly or incompletely (for example, having only boundary=administrative in a node without anything more)
• something else that I don't remember :-)

Could it be possible to find those objects in JOSM? (both via Search and with MapCSS (to use in a validator rule), if possible)
At least for me it's a good way to spot wrong objects.