It's been discussed here on the forums a few times the issue with infinite scrolling and footers. When it was first brought up I didn't think it was that big of an issue and wasn't that common on the internet. Apparently I was wrong because I recently found an example of the issue on a extremely large site!
I was on Nike's website and wanted to locate a store near me. Usually the 'locate a store' page isn't linked in the header, so I knew to look in the footer. I start scrolling down to realize I wasn't reaching the bottom of the page! I pulled my scroll bar to the bottom to see the footer only for an instant.
Here is the example for those who are interested.
