If a motorist hits a cyclist, they often try to excuse themselves by claiming they "didn't see" the cyclist.
Why, therefore, do any motorists expect us to take them seriously when they oppose bike lanes because they claim they "don't see" many cyclists using them? Personally, I think the best answer to a motorist who claims not to see cyclists in the bike lanes goes like this: since you need to look where you point your car, and you shouldn't point your car into the bike lane, your not seeing cyclist in the bike lanes just proves you drive carefully. It does not, however, prove anything about the number of cyclists using those lanes.
You can't take a census and drive at the same time. Even Statistics Canada doesn't drive and take the census at the same time; they get out of their cars to take the census. Why some motorists think we should believe they can take a census of bike lane users as they drive I don't know.