Well given the state of Brums roads, they must cope better than you'd think.
Maybe the length of them and way the forces are distributed means you simply can't get flung over if you hit a pot hole ?
Where they really are a menace is when you are trying to emerge from a side road, and one shoots across in front of you on the pavement where you aren't expecting to see something/one doing 15mph.
In times gone past, they'd have parked up for the winter and hopefully never be seen again. But this climate change malarkey seems to have made the milder autumn and winters a scooterists paradise.