Hmm... I have my doubts as well. Some days ago I initiated a tranfer from a coinbase wallet to another of my wallets, and it was pending for almost 48 hours. It was only .10 btc, but still i found it a bit suspicious. It would just sit there as "pending" with no further info, and you could tell that it was not pending in the "waiting for confirmation" way, but had not even been broadcast to the network. Got no real answer from their support either, but did get my funds transferred when i started posting about the problem on their support forum and emailing them. After 24 hours, that is