It's fairly common for companies to pay for journalists to attend events that are important to the company and the brand, just that for the vast majority of ethical journalists it's well understood by both parties that it does not imply favourable coverage. Some, like The Verge, refuse to accept any payments for junkets whatsoever because of potential ethics issues, but that doesn't mean that all journos who do accept those invitations accept to be paid shills.
Ethical companies understand that and accept the risk anyway, because getting good journalists with reach to even think of your brand and see your devices in the metal in the right circumstances is much more difficult than you'd think. So they put aside a relatively minuscule part of their marketing budget to wine, dine & sometimes fly journalists to these events.
If you look for it, you can often see this being disclosed by the relevant journalist at the end of their article, depending on their publication's ethics rules. For instance NYT journalists like Mossberg and Pogue will mention when a new Apple gizmo they're reviewing was shown to them personally by Apple before the public unveiling.
I have insight into this because a number of my friends are journalists across a few different industries. One in particular (not in the tech industry) was just recently flown to an event in Europe along similar lines, with the only requirement being that he was asked to attend all the particular company's press briefings there in return.
Samsung's behaviour in this case is unethical, to blame the bloggers for any of this when it's clear that they did their best to clarify the arrangement is unfair.