I find it interesting that people who have no knowlege of local laws and riding conditions still feel compelled to judge the relative safety and legality of sidewalk use.
I've spent a fair bit of time in Hamilton, but I am not familiar with that particular stretch of road, and I am not going to second guess these riders choice to use the sidewalk in this scenario.
Perhaps the fact that they were on the sidewalk caused the problem they describe. Perhaps it was not a factor. Perhaps it was safer. I wasn't there, I don't know.
But somehow many posters here seem to know all about it.