Do you have a link?

Was it similar to what we’re seeing now (nationwide, radio related)?

> it was confirmed that Russians did it.

>> It’s believed the perpetrators of the attack were supporters of the Russian war effort, as the stop signals were also joined by broadcasts of the Russian national anthem and a speech from Russian President Vladimir Putin. The attacks have some significance to the invasion of Ukraine, as Poland has been a hub for crucial weapons deliveries supporting the defence of Ukraine.

Yes, yes, it's a code of honour not to use the someone' else national anthem, sure. Especially if you need to bolster the population support for some ongoing cause.