Legal? - possibly. Ethical? - not to me. How is this not evasion of labor laws? That this is par-for-the-course is pretty dismaying.
It can be a lot of fun if you know what you're signing up for.
This should be EXPLICIT from the beginning
"It's targeted toward students that are tech-savvy"
Newsflash Samsung, Bloggers != 'tech-savvy students'. It may overlap, but don't count on it
Surely Samsung aren't doing this for the work -- there have to be cheaper ways to get people to demo your product than flying folks from India to Germany, getting them uniforms, keeping close watch on their activities, daily update emails in the beginning, etc.?
Why not just have their own employees do it? Or just pay native German bloggers?
It sounds to me like Samsung was trying to buy enthusiasm, but failed to adequately communicate the work involved and then massively overreacted when it went wrong for them. With decent management, it could have been better the alternatives -- the 'booth-babe and slimy salesman' or 'bored employee droning through a script' approaches.
I still prefer Apple's approaches to product demonstration -- either a big on-stage demo followed by relatively unsupervised hands-on time for a large number of reporters at once, or a personal demo by a senior executive for certain lucky individuals.