tuft testing

I was reading and saw a picture of a wing being tuft tested. I was
wondering, since I do not have a clue, how much difference the tape holding
the tufts would cause. In the picture it appears that 1/2 inch blue masking
tape was used and it was torn rather than cut. The tufts were spaced a
couple of inches apart and there were seven rows and eight columns. His
results were that the wing was not showing any separation. Just wondering
if there are accepted methods of doing this type of testing? How would you
determine where to test? Any discussion and comments would be appreciated.