Cheaper to redirect than increase capacity, I suppose from an ISP point of view, if they have a under utilised link and one thats full, they might see it as wasted money to upgrade the fully loaded link in preference to sharing the load with the lightly loaded link, so depends in the ISP values their balance sheet or service quality more.
This sort of stuff likely happens commonly on transit providers, but when its extreme like going to the opposite part of the country first is when consumers start to notice.
VM Gig1 - AAISP L2TP