As it was mentioned before it may have been too dangerous, if the lane is full of glass or junk as they generally are, riding there may not only make his journey longer by having to change tubes but could also put him at risk as if he has a blow out controlling the bike can be a bit of a mission at best.
I have many times had to continue riding up to 5km to get to a bike shop with 2 completely flat tyres and it isnt easy just because the council doesnt find it necessary to clean the bike lane regularly. It would be comparable to every time you drive on the freeway you get a blowout, how likely are you then to drive on the freeway?
When it comes to riding two abreast it may have been a tactical thing like riding in the middle of lane it could have even been just one stupid tool driving next to them that they thought it may safer untill they get onto quieter roads.
I can tell you one thing that when I go out for a road ride on my BMX or mountain bike the game changes alittle as bunny hopping up and down gutters isnt an issue and dare I say darting across traffic(between safe gaps). It is definitely alot safer as it takes the whole car thing out of the equation, but once again because of a few, the media turned on this and its frowned upon.
A road cyclist has no choice as he cant go up and down a gutters when a situation gets hairy, there only option is to make the situation as safe as possible before something goes wrong, and its easier for them to assume that every car is driven by someone that either doesnt know how to drive and doesnt want then there.
In a perfect world where cyclists and drivers got along and people watched out for them tactics of the cyclist would be a thing of the past.
The closest place I have been to for this was Dresden, Germany.
Now just to make sure I am not supporting in any way to action of those that dont have a clue when it comes to riding on the road, but the media and the general attitude of us australians has turn us cyclist into an evil force and in general everyone always cracks first before that look around to see as to why they might be doing what they are doing.
One incident of my own was on a road with bike lanes that were clean everything was going fine until there there was a slight bend in the road where the council obviously decided wiithout concern for those on the bike lane, that cars were having an issue with this area and put an island on either side of the road and one in the middle with reflective arrows(Im sure you know the ones), I pulled onto the road clear before it with no one anywhere near me following but when I got to the Islands a B double truck decided to pass me through them whilst blowing his horn, could I have been killed? yes. Why didnt he slow down for half a second so I could go back to the bike lane, who the hell knows. It took me almost 5km to chase him down just so I could have 10 seconds of anger ventilation lol but it made for a good ride, I really push myself on that one lol.
Sorry for the blabs and venting guys but it kills me when people talk about cyclists as because the media continues to continuely shape australias mind everyone is putting all cyclist into that same boat. I cant tell you how many times I have been in a car with non cyclist friends, randoms and even my GF and they either mumble a few words as they pass a cyclist or even abuse them when they are cleary riding along to the left of the left lane in a neat and tidy fashion.