There's a number of assumptions in that sentence that I 'd like to challenge:

a) That people act as rational beings and will at the next elections vote to their best interest. b) That people have the information to gauge whether taxes/resources are spent wisely c) That the main contributing factor to people's voting preferences is taxation or spending of resources d) That there is a lack of disinformation campaigns that will actively try to sabotage both a) and b)

And that has happened (for a very very long time now). The key problem being "enforce". Enforcing works up to a point and there is always the need for a cooperative public. The moment the public is distrustful of this institution (or any institution for that matter), everything goes down the drain. Look at https://ec.europa.eu/commfrontoffice/publicopinion/index.cfm... for the level of trust in the government greece has.

1) That panel exists in a variety of forms. The problem is, how do you nicely estimate land value in an economy were real estate transactions are few (which is happening for the last 10-12 years or so)? In many places it's impossible to estimate due to the above, so the alternative is to rely on very old values which are going to be out of date and don't reflect reality. And you can't put 0 for the land value as that would mean 0 taxes and the state financial situation does not allow that B) That is happening. Dispute is problematic as it takes years for the courts (yes, with the exception of blaring mistakes, the state has no incentive to accept that a land value estimation is wrong, so courts it is) to come up with a decision (never mind the fact that it will be appealed anyway so even more time and money spent on this), but it is happening. C) Again, this is problematic due to the same reason as 1). There aren't really that many real estate transactions to accurately estimate land values. Everything went into a pause for years in a row.

"The scheme is a radical attempt to cast some light on Greece's huge shadow economy, the world's largest"

and let's look at https://www.theglobaleconomy.com/rankings/shadow_economy/

wow.. wait, Greece is barely at place #86 out of 158 countries. Hmmm someone did not do his due diligence here.

Then we have the following.

"Greece also has one of the lowest internet usage rates in the EU at 72 per cent". Per https://www.internetworldstats.com/stats.htm it's definitely not great. Trailing by at 45/54. We can remove Vatican City, San Marino, Isle of Man, Svalbard and Jersey (all have lower rates) and say that's true. But it's written way more sensationalist than it is. The mean is at 87.7% so there is definitely room for improvement.

At least the suggested result is pointed out like that, i.e. "This suggests that some in the country could struggle to meet the 30 per cent target". Not sure why, but anyway.

And then we have a repetition of the argument above

"Southern Europe, particularly Greece, have booming shadow economies. A study by the Institute for Applied Economic Research in 2017 found that Greece had the largest in the world, being equivalent to 22 per cent of gross domestic product."

Wait, which country's Institude for Applied Economic Research? It's not at all mentioned. Googling it, it turns out it's Germany and the actual research is at http://www.iaw.edu/index.php/aktuelles-detail/734. The actual number of countries studied? 20. Not sure what the criteria for their selection were. Out of a planet with 195 countries that's barely enough to justify the above (and the original research does not make such sensationalist claims) never mind the fact that countries like e.g. Thailand have double that rate.

Overall, kind of meh.

Per https://www.transparency.org/cpi2018 Greece is ranked 67 out of 180 countries in the corruption index with the admittedly not high score of 45/100. 100 is not the top at the score, Denmark is at first place with 88/100. So, relatively speaking, corruption exists all over the place, and Greece ranks mildly ok compared to the world. It also ranks better than all of it's neighbouring countries. Compared to the US or the EU, there's a lot of room for improvement of course.

So there's probably more facets to the problem that just corruption.

That does not compute. How does one prove that 30% of their expenses were done using electronic payments? Submitting paper receipts for the other 70%? It's been tried and it's unfeasible.