No. paper stencils are the better way.
Just remember the softness of the edge of the camo is dependent upon the distance that the mask is away from the surface. Therefore the closer the mask the sharper the line, and vice versa. Also always spray perpendicular to the mask to prevent under spray leading to an overly soft edge.
The camo in these pictures was partly done using the card masking technique, just to show it can work, mainly the patterns on the engines and wing edges.
http://img78.photobucket.com/albums/v351/KT200/000_0093.jpg
http://img78.photobucket.com/albums/v351/KT200/000_0089.jpg
http://img78.photobucket.com/albums/v351/KT200/000_0088.jpg
http://img78.photobucket.com/albums/v351/KT200/000_0091.jpg
It takes a bit of preparation, but it does work.
Hope this helps.
Karl