Honestly I find it hard to believe that was a real bet. Is there any proof anywhere?
What like a screenshot
I dont see why its so hard to believe that someone, somewhere in the world stuck $20 on 7-1.
For all you know they could have had $100 to bet and thought that Germany were likely to win by more than 5 goals (I bet they would win by more than 4 so its not hard to believe). Then to hedge their bet a bit they had $20 on 5-0, $20 on 6-0, $20 on 6-1, $20 7-0, $20 7-1 this is perfectly plausible.