Justified fear. A former flat mate of mine reported an unexpected outgoing transfer to his UK bank and they blocked his account for 3 months. He was essentially unbanked. He had to pay his rent in cash after getting it from an ATM with a credit card (which cost a lot extra and hit limits). Resolving it took months even though we lived right next to a branch of that bank, where he went every day.

I had a situation where my mortgage took money from my account, but used the wrong company/reference name.

I didn't know what it was so I clicked a few buttons in the app and the money was back instantly.

That was on Commerzbank. Dunno if others are the same!

The issue is more "I checked my account yesterday, I have 600€ on there, so I know the 150€ utilities bill due today is not an issue" and then a weird withdrawal happens and all of a sudden the utilities payment bounces. Even if i get the money back instantly once I notice it theres still the issue that now I have to deal with a bounced payment to a utilities provider.

But no company cares about an occasional failed payment? That's part of doing business?

So they send a polite email informing you of it and you pay it a few days late?

No reasonable entity would charge late fees as that's a great way to anger otherwise perfect customers?

But again, I am not talking about myself, im talking about the hyptothetical person who might not be the perfect customer. My in-laws have had their gas cut more than once because of non-payments, or were only allowed to keep the gas running because they told them "we will wire you the last 3 unpaid invoices at once on day x".

For me to personally end up in this situation the bank would need to somehow SEPA out like 2 years worth of mortgages at once in a short timeframe, which is not a realistic scenario.

If you have an app, you'll notice immediately that a payment bounced, via notification. If not, you'll get a letter informing you that it bounced.

Also: it takes A LOT of letters and court orders for them to cut your utilities. I'm not joking, it's more than a couple of Mahnungs, then it goes to debt collection, then it goes to court. The court will then take the money out of your account.

That's all before power gets cut.

It definitely won't be because of a single missed payment.

Even in the situation above: if your in-laws somehow had no balance "at once on day x" because of a fake SEPA, they would be able to reverse via app, or go to the bank and reverse.