In the end, the consequences will be dependent on the real cause of the delays. If Citibank is indeed blocking transfers to MtGox, other American banks might adopt the same policy...
https://mtgox.com/press_release_20130704.html
"Current Back-log
The new system is just now getting under way, so there is still a back-log of withdrawals that we need to process. Our team is working hard to increase transaction speeds, but there is approximately a two-week back-log we need to overcome. It will take a few weeks to get back to normal, and we thank you for your patience during this time."