I'm thinking of leaving my two year old on the swings while I go grocery shopping.
Two years old is very young! You can't leave him there alone, can you?
He isn't all alone. There are kids nearby that are playing with each other.
Leaving your children unattended is generally a bad idea, particularly when they're very young. A two-year-old left alone on a swing is likely to fall and get hurt, and if you're not there to help then other adults may call the authorities on you. You need to have an adult guardian watch over your child if you can't be there.
Nah. Just got to get shit done.
I can understand that you are pressed for time, but it's too risky to leave your child alone while you are on an errand. If there is no one that you can call to watch your child for you, you should take him into the store with you, and then go with him to the swings afterward. It will be time consuming, but it is best for your child.