Yes, that's what I would do if the crock pot method was the only one available. I'd simply put it into the crock pot and let it sit until it 'looked' right or felt warmed through upon checking.
The boiling water isn't essential, it just speeds things up obviously. Before I had boil safe bags I'd put a towel in a pot of water, then throw the ziploc bag into the pot once the water was simmering, and it'd take maybe twenty minutes or so to get to the temp I desired. If I threw them into boiling water nine times out of ten the seal would break on me, and fall into the pot. Lost a few family sized portions discovering that. Once I got a Foodsaver and started vac sealing all my portions I started to use the ACTUAL boil in a bag method.
Both gave me good results.
I'd use the High heat setting, and I'd do it first thing upon getting to work assuming that it's going to be a lunch time pot luck. With my crock pot set to high I figure it'd take about 2-3 hours for the water to get to a decent temp. I'd be checking on it at about the hour and a half mark to see its progress, and then I'd check every 20-30 minutes after that. Once it gets hot enough you can just set the crock pot to the warm setting, and it'll hold it nice and proper. Make sure you're using good quality bags if you don't have access to a vac sealer, or double bag the stuff.
The Life of the Knife is Ended By! The Wife.