Organizer Hanspeter Balsiger told local outlet Blick that precautions were taken before and during the voyage.

The trip included a folk-music themed cruise, as well as hours of singing in enclosed spaces. According to one passenger, Daniel Kissling, while social distancing was maintained, not all passengers were wearing masks during the music-making.

In fact, public health experts have identified group singing events as a high-risk activity because of the potential for droplet and aerosol spread.

However, the organizer said that they had not received any prohibition from the Federal Council.