There’s was a change a little while back (Unrealistic speed when stopping pedaling - #9 by DavidP) to the speed that the game will brake you down to zero speed - so it’s possible that previously those bumps would bring you down to under 27km/h (which would cause the game to probably bring you to a halt - I too have vivid memories of coming back from a post-climb shower to find the avatar stopped on a -2% gradient mid decent), but not to the now-much-lower 15km/h that you’d need to be going in order to come to a stop.
To bring this reply back on topic, it makes me sad to see people disregarding the “be honest” notice that’s on the in-game profile screen next to the fields to input your weight and height. But then, (and I realise I’m showing my age), I know of people that boasted about cheating on Wii Fit back in the day, so little surprises me.