Connect event

I have a gateway connected to a pub/sub bus where everyone who is
eligible and connected to the bus should receive an event with a thing
description when a device has connected, disconnected, or changed. There is
no action required or any way to opt out for such events. When I try to
model this in the thing description I end up with an event like this.

{
  "connect":{
    "title": "Device connect",
    "data": {
      "@type": "Thing"
     },
     "forms": []
  }
}

The forms attribute is mandatory, but there is no way to explicitly
subscribe or unsubscribe to the event. Is an empty array like this
valid. What I really would like is to have an "op", "unsolicited" to inform
the consumers that unsolicited events may appear with a given href.

{
  "connect":{
    "title": "Device connect",
    "data": {
      "@type": "Thing"
     },
     "forms": [{
       "op": "unsolicited",
       "href": "event/connect"
     }]
  }
}

It may not make much sense as a form since there is nothing you can do, but
it will give a href and identifier for unsolicited events (or propagated
property changes in an unsolicited way). Any thoughts?

//Tuve Nordius