Landlord will only accept cash

Irish people hate anyone who they think is better off than them. Fact. We are famous for it.

In this case the posters see someone getting some money that they arent getting and the hate grows in them.

What harm in reporting her to revenue. Yes it's only a suspicion but the evidence presented here would seem to suggest there's a reasonable chance there is some tax dodging.

If the ll is above board she has nothing to worry about.

By all means but I've already been audited by them. Its not that bad, if you've nothing to hide.

You're very defensive... Something you're not declaring?

Believe me, I pay enough tax for us all, and the only thing I haven't declared is my disdain for people who feel the need to involve themselves where its unnecessary.

Being audited is an inconvenience, and like most other people I use money to avoid inconveniences as much as possible, I can clean my windows myself but I don't, why? cause its an inconvenience so I pay a window cleaner, that's how the world goes round, I pay the window cleaner in cash - maybe I should have him audited?

Depends on the individual circumstances, in this scenario lets say the op is accurate and the income is 40k for this property and there is tax evasion, but also lets say the landlord has a family member with bone cancer and the money is going towards treatment, of course this is not likely but its also not impossible, it just depends on what you want to consider. The difference between people like me and people who will jump on the phone to revenue is that I'm open to considerations.

The information or evidence you have in your possession should determine whether it is appropriate to contact revenue and put another person at such an inconvenience. In the case of the garlic man I'm not sure exactly how the revenue became aware of the case, however in this instance to contact revenue based on a boards thread whereby a landlord has a preference of payment in cash is completely an overreaction.

You are contradicting yourself now. Do you not see the irony of you jumping to the landlords defence, and castigating anyone suggesting the OP let the Revenue know, because you don't know that they don't have a relative with bone cancer, but then saying that it should be based on the "information or evidence you have in your possession"

You said:

when you have no evidence or information that it is unnecessary.

You haven't told us what is the harm or the OP letting the Revenue know in the event that the Landlord has been doing things properly? If they are, the Revenue will take a 2 minute look at their returns, decide "nothing to see here" and the Landlord will be none the wiser

One would have to be a bit innocent or extremely naive to come to any other conclusion given the circumstances as described.

Cut from different cloth I guess, I would see those who feel the need to alert revenue at any minimal sign of cash payments as innocent or naïve.

Could also be a delinquent mortgageholder situation.

There were the stories a few years back about properties being repossessed where the "owner" was collecting rent but not paying the mortgage for years - just delaying repossession for as long as possible while the tenants were oblivious.

OP has already said they are leaving, so your point is moot.