Okay.......
Wrap, translucent, digital, die-cut, overlapping on a solid substrate, close viewing, distance viewing......... all these things will probably have some bearing on the advice you'll get.
To tell ya the truth, I don't know about reflective. We've never overlapped reflective. Always got the size roll we needed to avoid it. I don't think overlapping such a thick media would be a good idea. However, they do it for state signs and such..... ya know, those big green ones up on the highways, but no one is looking at them going much under 65 mph, so I don't think anyone is complaining about a little overlap. When they wear out, they just spend more of your tax dollars to replace them........
I could be mistaken, but I don't think highway signs have overlapping vinyl seams. Here in Canada at least, the big green signs are made from several smaller panels of aluminum, which eliminates the need to seam the vinyl.
Back on topic though, I'm not sure how much a seam on reflective would stand out on a vehicle, but it would probably stand out more than with regular vinyl. One tip would be to make sure the pieces are cut in the same orientation on the reflective film.