My information is not based on studies, but is anecdotal. I'm in an environment where lots of people travel lots of places, and it's just not seen as an issue. Having heard this morning that our eTA would be for five years or for the balance of the term of your passport...I think it's not going to be viewed as a barrier in any way to travel. That's just a personal opinion.
On November 19th, 2012. See this statement in context.