D.,
My husband and I also swatted our son. He is five now and has wonderful manners most of the time. He tried screaming in the store a couple of times, but I would take him over to a secluded corner and give him one swat though his diaper. We only needed to do this a few times and he got the message. He has never hit another child so I don't believe in the message that swatting can make a child confused. I think that most parents lay out set rules and children know when they are breaking them.
Example: at age one we told our son not to touch the stove/oven. He would walk over to it specifically and touch it with a smile on his face. The first few times we told him no, it's not safe. The third time he got a swat through his diaper. Every time after that he received a swat first time because he knew that the stove was dangerous and he just wanted to get our attention and see what we would do. It took very little time for him to lose interest in the stove.
I think that there are times when parents need to enforce the social rules. In addition to swatting, we also used timeouts and put favorite toys into the treasure box to be re-earned. But in the beginning our son only responded to the swat.
Again the important step is to never do this in anger. A few times our son pushed my buttons so badly I sent him to his room so I could cool down. When he was older I explained to him why I was angry, but if my husband was around then he would give our son his punishment while I cooled down.
I hope this helps! Good luck.