Mats Olsson went over to Copenhagen in 1971.
He returned with a report of how the audience acted during the concert.
Not very much was written about the group, except for these intruducing lines which say:
The popindustry has never seen such a disguisting group as Grand Funk Railroad. The group consists of three young men, who have been used by clever PR-guys to become "The New Beatles" in the USA. I hope somebody destroys their ambition to make it in Europe.
The same rockwriter four years later:(writing for the leading newspaper EXPRESSEN)
Grand Funk is coming from USA and is classified as the LOUDEST group in the world.
I saw them in Copenhagen a few years ago - it was a horrible event. Since they kicked their manager, they have earned more respect - but still, their music is poor, without real feeling and engagement. It´s just loud and heavy.

From Expressen in 1999: a review of TYOF which is
headlined "More from the Dump of Rock"