All of this reinforces that with older scanners that you need to have all the talkgroups in a patch (396T), Make sure that you have the MTO Enforcement, the MNR talkgroups in your scanner, if not you might miss out and post here " umm duh, why aren't I hearing my local talkgroup anymore." (Please keep a sense of humour here, I am not trying to be mean-spirited).
I have been seeing a patch with Middlesex and Elgin units with one of the MTO Enforcement talkgroups dispatched by London recently. There are occasional MNR patches with the Caledon OPP talkgroup, even the usually "stand alone" talkgroups of Norfolk and Oxford find their way on patches either together or with the MNR and MTO Enforcement talkgroups, London Dispatch.
People are on holidays, maybe the dispatchers feel that with more people in parks and camp sights, at provincial beaches that they will patch the MNR with regular OPP talkgroups that are already patched with the MTO Enforcement units.
As Forts mentioned, Trunk 88 will show all of this. You hit CtL P & you are going to see what is patched with what, when the patches are down, when they come up. Newer scanners make it easy for this, load up Trunk 88 and let it go as you scan a particular tower on the Fleetnet system.
Sadly, you are left to use Unitrunker if you desire to follow a EDACS system like Waterloo or the newer P25 systems like Metrolinx in the GTA, Halton, etc.
Trunk 88 and Unitrunker are important tools, showing what's going on.