Busch-Jaeger Presence detector masking

[Jeecha]

I plan to use BJ presence premium and mini premium in few locations where sharper zone separation is needed. I got one BJ mini premium (6131/21-24) to play with and zone separation works very well. However in some planned locations the maximum detection distance is too large. Some painter's masking tape on the outer edge worked wonderfully to limit the range to exactly where I want it to be. In actual installation I would use something like white Oracal film to make the masking almost invisible.

Is masking of BJ detectors an acceptable practice?

[Beleuchtfix]

If it works and the owner does not object the design why not.
Regards Florian