I am a freelance video editor and a client has asked me to compile an ad meant to be used as viral video. It involves compositing into their ad several viral videos from youtube like the darth vader VW ad, cats on treadmills, Evian babies break dancing, charlie bit my finger, and some sexy girls in bikinis that we shot, The voiceover says something like "we won't stoop to using viral videos and sexy women to grab your attention." I'm concerned that my clients don't have permission to use the content in this way and so might get sued. Are they violating DCMA or other copyrights? And i so, can I get them to sign something to indemnify me as I am a sole propietership and have a lot of exposure if I get sued.Sorry meant being sued.