This is a good point. Honestly the most annoying thing will be the polluting of fb feeds with checkins (something it is possible to ignore from others I believe, but not prevent from posting yourself if you check in on fb... which is the whole idea of course)
It already has this problem, and its solution was to default sort to "Top Stories" instead of "Latest Stories." A lot of accusations that it was a money-grubbing play for pay-for-performance, but I don't think they had much choice. They had to fix the problem of a few noisy people, pages or apps dominating users' feeds. https://news.ycombinator.com/item?id=5320207
