I wouldn't do it, Dave. You risk binding the masks to the paint layers, and potentially increasing the size of any paint ridges that might form against the edge of the masks. I'd recommend removing masks (of any kind) as soon as you can after you've finished laying down any paint. This not only minimises the opportunity for the adhesive on the masks to do any damage to the underlying paint, but also allows any paint build-up against the masks (ridges) to self-level, depending on the paint you've used. Once the masks are off and the paint is completely cured, you can reduce or even eliminate and ridges by gently rubbing or polishing the painted markings. At that point, you can start doing your clear coats.
Of course, some or all of these things are not always possible - especially if, like me, you tend to paint markings first, mask them out, and then paint the camouflage colours later. It always pays to experiment on a mule if you can! But in short, don't add a clear coat before removing masks.
Kev