Does helicopter money have to be paid back ?

The definition of helicopter money is a bit fuzzy. One can hear a ton of different propositions on what it will entail or how it will be carried out. Α point of the whole debate that I find hard to grasp is that some commentators state that helicopter money doesn't have to be paid back to the central bank.

In all past applications of helicopter money that I've come across (and I've looked at quite a lot of CBs' balance sheet these past few months) helicopter money were recorded in the asset side of the ledger as a General Government's liability towards the local CB. 

For example here's the 2015 balance sheet of Bank of Greece.

source: Bank of Greece

If helicopter money doesn't have to be paid back it means that the relevant CB's capital will take a hit.

In the past such General Government's liabilities were paid back. 

Here is the example of Bank of Greece.

source: Bank of Greece

What's more, as far as BoG is concerned, in 2001 General Government's liabilities to the CB accounted for almost 33% of its total assets. The term, fiscal dominance springs to mind...

source: Bank of Greece

In case of Banco de Espana, helicopter money was repaid as well. 

source: Banco de Espana

It states that explicitly in the balance sheet's footnotes anyway.

source: Banco de Espana

The same goes for Bank of Italy.

source: Banca d' Italia

Here the said General Government's liabilities were converted into bonds.

source: Banca d' Italia

 If helicopter money doesn't get repaid and the local CB takes a hit what will the impact on CBs' credibility be? Are we sure we want to go down that road? Because it is perfectly possible that while trying to solve one problem we might end up with a bigger one in our hands.