David of Broadway wrote:
(The person pushing the button would be caught on video, so he might not
want to push the button frivolously on a regular basis.)

You mean in the same way that town centre CCTVs do such a good job
of catching peoples faces when they're wearing a hoodie? Besides which
unless the camera can ID someone by their eyes then all someone has
to do is put their arm in front of their face as they go through.

B2003