I thought the title of the thread was a little funny because of course lots of people all over the web have been getting the CSP, and more recently the CSR, just for the sign on bonus. Big bonuses attract that behavior, and the issuers expect that some portion find that they like the card and keep it.
So re what is safe: I would assume that Chase knows that some people have no intention of keeping the card and paying the AF, they may not care that much unless you have a repeated history of doing this. But, since Chase can take very drastic AA in some cases, I would just do the least suspicious thing, keep the card for nearly a year, and once the annual fee is about to become due, cancel or downgrade them, hey, you gave it a try but you cannot justify the AF... Relatively normal for any AF card. Changing as soon as you get the bonus signals your motivation, even if Chase doesn't care at that point.
