I recommend making sure your fabric is completely covered before you start spraying. On the first bag I stenciled I thought I had the fabric sufficiently covered, but some spray paint managed to float under the newspaper I used so there's a faint spray paint line on the side and top of the stencil.
It's not too noticeable, so I'll just keep this bag for myself! On the second bag, I made sure to tape the paper down with masking tape. I love this stencil so much, I want to make a cute shirt for my son. Thanks for looking!