IMO; if we take away the 'play or not' issue; we are still left with a dog off leash in a public place and an owner with questionable/ negligible control.
I find this unacceptable regardless of breed or even if the dog is friendly or not.
Quite frankly, I will state my opinion to any owner who approaches me and my dogs with their dog off leash. I also let them know that if my dogs (on leash) injure their off leash dog, I will not be responsible. Any off leash dog who bounds up to and in between a bonded pair like my guys is asking for trouble, hence my dogs are never off leash in public. End of story.
I have also been known to leash the off leash dog (I keep a supply of cheap leashes for this purpose) and tie it to a tree/ fence so I can leave. On occasions where no owner is to be seen, I might leash the dog and deliver it to the pound.
I'm not flexible on this issue- and I fail to see why putting a leash on a dog is so hard.
I also chose to avoid areas I know are prone to uncontrolled dogs and idiot owners