I know that this suggestion has been posted before. But I would again raise the importance of this feature.
You all experienced the issue where you call somebody incidentally while your phone is in the pocket, and its every time the wrongest person you could have accidentally choose to call.
This could also happen with the Blynk App; what happens if you accidentally open the Blynk app and press the button to open your garage door at home. You will say that this situation is nearly impossible, but think about the "incidental call" example from before. There are probably more critical situations like this one.
It would be really nice, if we can keep the controlling widgets in one tab, and lock this tab, maybe even with a simple 4 digit pin code, this way we would be sure that nothing can happen even when your child is playing with the phone.
The workaround is to logout, but this makes accessing the monitoring part of the app very uncomfortable; lets say, beside your garage door, you also monitor the temperature in the garage...