I'm not sure what the latest situation is on "pink slips". I am tax resident so they are not relevant to me. I will make a couple of comments, however.
First you need to understand why pink slips were used. Greece operates a system of presumed/imputed income. In the UK HMRC will sometimes look at a person's lifestyle and compare it with his declared income and if the former seems lavish given the income they might investigate further. It is all a bit arbitrary. In Greece this has been formalised such that certain assets mean you must have a certain income. You own a house of A sqm means you have an income of €X. You own a car with an engine of B cc means you must have an income of €Y. You own a boat C m long means you have an income of €Z and so on. Your presumed income is then €(X + Y + Z). If you declare an income more than the presumed income you are taxed on your declared income. If you declare an income less than your presumed income you are taxed on your presumed income. This system used to apply to everybody and so ex-pats, who had no income in Greece, had to demonstrate that they brought an amount of money each year into Greece at least equal to their presumed income. If they didn't they could be made to pay tax on their presumed income. This is an extract from a general email sent by my accountant to all his clients in July 2010 that illustrates the point:
Please note that the cost of living means that one (or a family) needs to prove that one has either earned in Greece the money or brought that money from abroad (only via bank transfers. Withdrawals from Cash Points direct from a bank, or cash deposits to a Greek bank account are not included) during that last or the previous years. If you cannot prove that, now you are going to be taxed at 5% or 18% or 24% for the rest of the living cost. So it is important to have an account with a bank located in Greece, transfer money to that every year (so that “white or pink slips" will be produced), and withdraw money from that account however you wish. In case that the house or the car is joined, it is very important the bank account also be joined.
Between 2010 and 2013 there were massive changes to the Greek tax code. I think at one point they issued 2,000 pages of new tax regulations in a few months some of it incomplete. The following is an extract from an email sent to all clients in August 2011:
Since 1/1/2011 according the new tax changes the individuals are classified in 3 types:
Type A: individuals that spend less than 183 days in Greece.
Since 1/1/2011, the rules that concern the imputed income are not applied to the individuals that spend less than 183 days in Greece with the precondition that they don’t have any income produced in Greece (neither hidden income). So there are no liable to transfer a certain amount of money in order to cover the cost of living.
The tax office will require some evidences that have to be companied the submission of your tax return each year. When the tax office will issue instructions related with what kind of evidence are required in order an individual proves how long he spends in Greece, we will send you an email.
So the presumed income is no longer applicable to people who are not tax resident, so pink slips are irrelevant, BUT the tax authority will want something but he didn't know what. I didn't pay much attention, since I am not in Type A but I can't find any reference to what the tax authority does now require. It looks like some people are being asked to produce pink slips by their accountants and some aren't. NfG. Collecting them cannot do any harm while not collecting them might so I would advise collecting them.