Is illegal to have Tinted/Dark License Plate Cover on my Plate?

Yes

Yes if the plate can't be read from a distance.

It is illegal to obscure your plate such that it is unreadable or difficult to read, yes.

It is as good as flying a massive flag saying STOP ME to the Police.

yes

i don't know

yes, they sell them online they use them to hide their plate numbers for tags and such. Saw this on CSI Miami a very long time ago...........................: ))