Yes, there's a large gravel area (which AIUI covers some sort of drainage infrastructure) at the other end of Cannon Hill Park that's routinely used for hosting funfairs and
Teletubbies Peppa Sodding Pig In The Night Garden Live events, which gets re-purposed as a car park in the event of the Commonwealth Games or (more commonly) Cricket. That's properly marshalled and is effectively Out Of The Way of people doing normal park things.
(There's
an area of Calthorpe Park that also gets turned into a car park for cricketers, which seems even more gratuitous.)
More usually, when there's an outbreak of decent weather, the locals flock to the roads around Cannon Hill Park to circle and hoot, before eventually finding somewhere to pavement-park. It would probably be quicker to walk, but if we're going to apply that sort of logic the Hagley Road wouldn't exist.