I view it the same way that nobody would look at a football (soccer) team's shirts and think "wow, those players must love that company!" despite there not being a "this is an advertisement" text on the shirts.
If I wanted to deceive viewers then I would change the terms of the deal to not show the 5 second clip or the floating 3D laptop, and to not have a link in the description of the video (or at least not one that can be seen to go through an adserver URL), then I would get him to make his comments about the laptop more subtle, but more frequent across all his videos. This would still be completely legal, despite having much more potential to mislead viewers, but certainly arguably less ethical.
Here [2] is an example of (non-YouTube) another thing I've done for a brand, to show that when it isn't already imminently obvious we do make sure that the paid nature is explicitly stated.
So: do you disagree with my judgement that there is no need for a specific note on such an obvious piece of activity? I would hope and assume you will once you see it, but if not then I'll certainly go get a few more opinions to see if I should change mine.
[1] http://www.youtube.com/watch?v=8CiQfMtSOgM
[2] http://www.pcgamesn.com/sponsored-post-introducing-qpad-prof...
I'd certainly suspect it - but it's presented as "oh look, I'm your fried, I just found this deal online". Certainly those less jaded by life, than I, I think wouldn't realise.
You of course would know because you know that companies are doing this sort of marketing - I suspect many people don't realise such endorsements are paid. Those more savvy would assume that the link below the vid is an affiliate link but probably not that the presenter was paid for the actual placement.
Which budget are you paying them from, advertising. What profession are you in, marketing. What are you hoping to gain from this project, increased sales.
You are using them to promote the product. They're paid endorsements.