lucy24 - 10:27 pm on Jun 5, 2013 (gmt 0)
A year or so back, someone posted about a hacker attack that affected only the mobile version of the site. The hacker seems to have reasoned-- correctly-- that the People In Charge would generally look at their work in the biggest possible format. So if you constrain your misbehavior to the less glamorous versions of a site, you can sneak under the radar for a long time.
Doesn't only apply to security breaches. If something visually disastrous happens at smaller sizes ("Whoops! That table doesn't really work when each cell is only two ems wide, does it?"), the user is not going to stick around and try to make things right. That was your job.