*hopes for a wired bank account*
At this point, it's up to DT.
However, this thought did occur to me today. Anyone who wants to determine the likelihood of DT playing at the Grammys can do so very easily with a bit of detective work (though I'm not going to do it myself because I'm already certain they're not going to play).
If DT were invited to play at the Grammys just now (which is, again, not a likelihood in my view), it's likely they were asked to play at the same time that a bunch of other bands were asked to play. Let's assume that this is the case. With that assumption in place, we also assume that this year is not an anomaly, and that invitations to play at the Grammys are usually given at this time of year. So, bands -- who, once again, determine their concert schedules several months in advance -- who are invited should be cancelling February shows in December as well.
SO: If someone found a few examples of bands that A) played at the Grammys in the last couple years, B) were supposed to be on tour that winter, and C) cancelled the shows on or around the date of the Grammys in the preceding December, this would be evidence for DT's playing at the Grammys (though not proof of it). Meanwhile, if no examples of this are able to be found, we can assume that our initial premise -- that bands are usually invited to play at the Grammys in December -- was faulty, that bands are usually given enough advance notice to schedule their tours when they play the Grammys, and that DT are genuinely just there to attend the ceremony as nominees.
If someone wants to take that train of thought somewhere and dig up some articles, we'd have some more convincing evidence, but, again, I sincerely doubt they'll be playing. It's just a ridiculous thought to me.