This app was mentioned in 16 comments, with an average of 2.50 upvotes
This app blocks the screen, you con configure how to unblock it (tripe tap, shake phone etc.) However, it doesn't block hardware buttons. For that I think it would require root permissions,
https://play.google.com/store/apps/details?id=com.argotronic.touchblocker
Try this app, it disables your touchscreen so that won't happen. I would recommend setting it to reactivate the touchscreen by pressing the volume button.
I use this app: https://play.google.com/store/apps/details?id=com.argotronic.touchblocker on an Xperia tablet to keep water spray/splashes from activating the touchscreen but I'm not not how it would work completely submerged. I assume you can start the video recording and then activate the app from the notification bar.
I'm using argus touch blocker on google play (android) found here:
https://play.google.com/store/apps/details?id=com.argotronic.touchblocker&hl=en
It has a shake to lock option and also can be locked via a permanent notification. It has triple tap to unlock. It works pretty well with battery saver mode in a well ventilated pocket.
I do my tributes on a tablet. not Apple. but this may help point you in the right direction. I had the same problem as you until i downloaded this Argus Touch Blocker I'm not sure if it's on iOS but it doesnt hurt to check.
basically it disables your screen unless you triple tap it in quick succession or press the power button on your phone.
Argus Touch Blocker on Android. You can disable touch from a menu bar shortcut and re-enable with a triple tap anywhere on screen. It's so quick and unobtrusive that most people won't even notice. They just hand your phone back like, "It froze, oh noes!" And you just tap and be all, "Works for me." Then remember that they're an attempted swiper and never show them anymore cat pics. Seriously, that shit pisses me off.
This is what I use
https://play.google.com/store/apps/details?id=com.argotronic.touchblocker
works great for watching porn in the shower because sometimes the water registers as a screen press
Touch Blocker might work for you. There area also a number of similar apps, though I don't know the pros or cons of each.
have you tired an app like this? https://play.google.com/store/apps/details?id=com.argotronic.touchblocker&hl=en
A quick Google shows this app (which admits problems with apps like Netflix), and two videos 1 and 2 show the LCD and digitizer cables. You can try unplugging the battery then unplug one side of the 2-pronged ribbon cable, power on to confirm that it's the touchscreen not the video, then seal it back up. iFixIt's teardown will show you nearly all the steps, they get to the cables in step 11 but skip over that specific action. Taking apart the tablet requires some patience and planning so you don't do further damage, but if it works you only have to do it once until you decide to replace the screen/digitizer.
did you try apps like https://play.google.com/store/apps/details?id=com.argotronic.touchblocker ?
I use Touch Blocker by Argotronic and lock my phone when handing it to someone.
Touch Blocker for Android. Try it out and tell me how it goes.
Use this app to disable touch and prevent skipping part of an episode or something
https://play.google.com/store/apps/details?id=com.argotronic.touchblocker
If you only want them to see a single image, then something like Touch Blocker can disable touch controls.