I have no doubt that students will cheat, people will cheat, people will cheat more if the stakes are higher. What I doubt is that this is any different to how it has ever been. The only thing that has changed are the tools available.
Prisons find it very hard to stop prisoners getting hold of tiny high powered computers which they use to access the internet. In other contexts they are called mobile phones. So if prisons have a problem, what is the chance of technology based solutions succeeding in an academic context.