Hey, ScottM. It depends on how the collective noun is perceived as doing the action, ie: is a whole force doing an action en masse, say, or is a whole bunch of individual doing a lot of individual actions. It's not one you can strictly apply the rule of singulars (now there's something) and plurals.
If you really want to get upset about something, take a stick to those who say the likes of "...there's a lot of birds in the sky..."
Am, or sometimes A(he)m.
Edit. Upon re-reading your missive I suggest you really try saying seriously "Tasmania Police is holding a fete this weekend..."
You're right! It does grate. Now if it were "...The Tasmania Police Force is...", well, I might go, myself.