Views on when to/not to allow a dog to be social

I am always willing to let my dog socialize if the other owner is agreeable.
I always keep a firm grip on my dog until I know they are willing to play nice.
If I determine they don't want to play nice I pull my dog back.
You don't know until you try.
90% of the time the dogs are fine. But there is that 10% factor when its not.
There are also times that it apparent that the dogs will not get along, no pull test rrequired!