Using the spray baste is how I learned to quilt. I didn't have any slippage problems it worked great. HOWEVER, I now use the curved safety pins. I hated how sticky everything was from overspray and there is no way that it can be good for you to breathe it whether or not your in a well ventilated room. And lets not talk about what it is putting in the environment.
Another added benefit from pinning...works out the back of my thighs and rearend. I am sore the day after basting due to all of the ups and downs as I have to baste on my floor. BONUS!