I have 4 shopping cart checkout pages.
3 share one cookie, #4 cookie is a different structure.
So the two cookies are stored in sequence.
It is rare that a customer would have both cookies saved but not impossible, especially for me doing tests from the same computer.
After processing the credit card, the bank returns to only one URL on my site.
On arrival I need to detect which checkout was processed and redirect to the appropriate "Thank you" page.
For the three of them that share a cookie I can save a numeric pointer but #4 uses a different cookie structure.
When I return I don't know which is current, both appear valid.