It needs people to use either a dedicated app or a wallet with the right features. I've gone back and forth on whether it's better to have wallets become featureful things or to have lots of separate apps. There are pro's and con's to each.
Fortunately bitcoinj makes bringing up a new GUI wallet app quite easy (well ... if you're writing it in java ;). So having a dedicated app just for managing your pledges is quite straightforward.
At that point it's about contracts programming: