Invisibility Shield

Want to be invisible?

The only real reason I can think of for this would be military. Especially if it has to be extremely thick. Even if it wasn't, though, what would be a real and good use.. sneaking into work late?

I can think of plenty of criminal uses. Much easier to be invisible in that case. Though on seconnd thought, they could be useful in theaters as well for types of scene changes or special effects. That would be fun.