In an ideal world we could all let our dogs off the lead to play happily together but it just doesnt work like that.
Even the friendliest of dogs can get into a fight and thats the risk you have to be willing to take if you allow your dogs to run freely.

I personally dont take that risk and put mine on a lead when I see other dogs aproaching.
That said if Someone saw me put mine on a lead and they still allowed theirs to run up to mine off a lead then they would get more than a mouthfull from me! Should my dog then bite the other dog, well thats their tough luck! Should have had control over it.

I think unless you are reasonably sure of how the other dog will react around yours then you should be cautious. Its common sense!

Of course dogs need to socialise and play so the responsible thing to do surely is to let the dogs meet on a lead (under control) and go from there?!

You wouldnt let your child run up to a strange dog you didnt know.

__________________
Lifes roads are for journeys, not destinations!