In heist or spy thriller films requiring the goodies to break into a heavily secure facility protected by advanced technology, one of the rooms en route to the target will be protected by laser beams (one only as well, for some reason). Sometimes they will actually be visible to the naked eye, sometimes they will require someone spraying something in the air to reveal them.
Luckily a member of the team will happen to be highly flexible and with acrobatic skills worthy of a circus performer, and will execute a complex yet graceful dance routine to reach the end of the room missing all the laser beams.
Imagine the trouble the protagonists of such films would be in if word ever got out that a bog standard £80 movement sensor from B&Q would be not just far cheaper than an advanced laser beam system, but far more difficult to evade…