
NO NO NO!!!!
You will know she is in season, but the owners of male dogs that are off the lead won't and they will make a determined beeline for your bitch, and you could find yourself unable to prevent a mating or even get in the middle of a dog fight.
Very unfair to the owners of the males whose instincts will overide training, as they will in your bitch, so don't be tempted to let her off lead anywhere and watch her in your own garden.
I walk my in season bitches on the lead only where loose dogs have no business being, in other words lots of pavement pounding :D