Just took advantage of this offer myself as I've been building up miles on Sapphire/Ink to move to BA as I have status on AA. Hit my limit of total credit with Chase but they were able to move some credit over (actually I closed an old Explorer card I had downgraded to a normal United Miles card since I wasn't using it). But didn't have any problems and she confirmed the 50K bonus appeared on account. Just need the card now to buy some Vanilla Reloads.