Well, for PT Distinction members this is not a problem you need to worry about. We've added autosave to the program builder. Your programs will now automatically save every 2 minutes (you don't have to do a thing for this to happen). If the internet cuts out, or you run out of batteries, or you swipe to the wrong page etc.. the most you can lose is 2 minutes of work.
Recovering autosaved workouts is easy...
If you're editing an existing program and you want to recover it from the last autosave go in to the program and select More > Recover from auto backup. Then it loads up with all of your hard work saved.
If you're making a new program and you lose your work there's still no need to worry, in this case go in to the program builder as if building another new program and once again select More > Recover from auto backup. From here your last auto saved program will appear with all of your work right there.
Here's some images showing where to click to recover a program from the auto backup.
Start inside the program builder and select More:
Then click on Recover from auto backup: