Have screen shots of the LMT tickets/email tickets on your phones, just in case the app glitches. After you go through the turnstiles, the CM will give you hard paper tickets (not the print outs like you got from LMT). The CM will take your photos (to attach to each ticket) and have you sign the tickets. Keep these tickets! First off, take a photo of each ticket with a clear image of the bar code and numbers. Keep the photos on your phone and your DH's. That way, if the tickets get lost/stolen and one of your phones goes wonky, you can still replace the tickets easily and quickly by showing the photos at Guest Services. (DISers have done this -- it works.)
Next, put the tickets in a safe, waterproof (DISers have learned this one the hard way! A ziploc bag will work or a Witz wallet) place. Even with the app and MP, you may still need these paper tickets. Occasionally (rarely) the MP system goes down, in which case you would need the paper tickets to use in the old fashioned FP machines. Lastly, someone just posted here today that their tickets disappeared from the app, along with their MP, so having the hard paper tickets in that case would be helpful, I would think, since everything would have to be rescanned. Just some thoughts...