Between which point specifically of the input ? Neutral connection ? Live connection ? Both ? Something else ? Specifically, many countries have a reversible plug (Germany(Shuko), France, Italy, USA to list just those I have first hand experience with) and so there is no way to know which side of the input will be "hot" as our friends in the USA call it.
I've just looked at a couple of our TVs and a DVD player, which all have 2 core mains leads. While they have fixed leads with brown and blue cores (I assume, moulded on plugs) I can't believe they don't use the same model with just minor changes (different mains lead, software, manual) across the whole of Europe or even the world. All have no earth connection (2 core mains lead), all have the square in square DI logo, but ...
All have I/O connections (antenna, analogue (eg VGA, 3.5mm jack), HDMI, USB etc) - and on one TV all these are on a large exposed metal plate, while the DVD player is mostly a metal case with no plastic covering. With the exception of the antenna input, I cannot see how the I/O could be isolated from the DC supplies internally.
So logically, it's hard to see how they wouldn't need two filtering capacitors - between PSU output and both sides of mains input (reversible supply in more countries than not). And it's hard to see how everything exposed could possibly be isolated from the DC busses internally (note that both HDMI and USB (and satellite on some kit) provide power to attached devices). So we really are down to the "chassis" being connected to a (weak) potential divider formed by two caps across the mains input.
In our house, the TVs (and everything else) will be incidentally earthed via connections to other stuff that is earthed. I do know that as I'm sat here with my laptop, I'm not currently feeling any of the "buzz" from light contact with the laptop. But if I grab hold of the end of the HDMI lead from the TV while touching the laptop, there's "rather more than just a buzz"
At one point I got out the multimeter, but couldn't get any significant readings for voltage or current between the two.
I can only assume that such an arrangement is deemed to meet regs - hard to imagine every major manufacturer making equipment with this arrangement if it didn't. But I'm with John on this - I'm "a bit uneasy" about the whole concept.
I have noted over the years that some equipment does have a spare screw with an earth symbol
So I suppose to understand why we get this sort of arrangement, we need to consider what would drive a manufacturer to use it. In the UK, and I guess most of Europe and many other countries, we generally take having an earth for granted. From various stuff I've read and seen over the years, I think we need to assume that having a reliable earth is far from universal. So does a manufacturer make something that needs an earth, and make it the users' fault if they kill/injure themselves by using a non-earthed supply arrangement ? It might be technically valid, but I could imagine there being a certain amount of moral and reputational incentive to not do that. So once you are down to not assuming a reliable earth, then makes sense to design for DI/Class II for those markets - and then you might as well do it worldwide and save the expense of two different designs of power supply.
That's how I read things anyway.