Just be sure you are only making ONE payment per billing cycle. If you make additional payments, those "extra" payments will go to the promotional balance rather than your regular charges/balance. So if you have a habit of making a smaller payment out of each weekly paycheck rather than one lump payment at the due date each month, only the first payment goes to the regular balance and the additional 3 payments would be applied to the promotional (vacation) balance.
Same for returns/refunds. For example, you buy a TV for $800 but then return it; you would expect that refund to go against the original TV charge but it will be applied to the promotional (vacation) balance and then you are stuck paying for the TV as part of your regular balance or incurring interest. Not a big deal for small stuff but it can mess with your balance and interest if a big ticket item gets returned.
Enjoy your vacation!