Rather than voting, as such, which is rather difficult to Police and check over the internet.
You could allow voting to ONLY take place, via the submission of short videos (such as youtube ones), in support of particular applicants. Stating why they are going for them.
These would be difficult to cheat, because you can see the individual(s), making each "voting" video, and their explanation(s) as to why they are voting for that video.
They may even increase the excitement of the event, which could benefit Keysight.
Also it would be nice if there were much more, low value prizes available. Such as Keysight multimeters, which cost a lot less than the higher end scopes. Then there would be far more winners, and reasons for entering.
Some people would much prefer Keysight to promise to supply the prize(s), such as scopes, inclusive of all taxes/duties (and income taxes etc). As long as the country permits this, and the charges are NOT excessive for that particular country.
E.g. Limit it to a max of 50% of the value of the scope.
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Another way of organizing the competition, would be to have a panel of judges, choosing who wins, out of the videos.
BUT allow individuals, to write comments, saying who they support and WHY. Then the judges can read through the comments, and use those to help them choose the winner(s).
Hence you would have many individuals involved with the voting process, but cheating would tend to be suppressed, because it is the judges who make the final decision.