Just tried it. If the phone is locked and you do this, the swiping up just reveals whatever other unlock method is set up (pattern unlock in my case). If the phone is in a trusted area or connected to a trusted device, swiping up at that point does open the phone without unlock, but that would always be the case. I'm not seeing an issue, but perhaps there's a specific set of circumstances that are the problem? But not being able to replicate the issue, I remain skeptical that this is an issue. I might try setting up a PIN lock instead of the pattern to see if I can replicate. (This is also on my Z Force, not Z Play, so there's a chance that's part of the issue.)