Many hotels in highly popular places do the same thing. (All Vegas Strip hotel for example,) Charging your card, even for refundable rates. But you can get it back, if you cancel it 24/48 hours before your stay.

I would recommend always to click on/read "Rate Details" - all these clearly stated on the hotel's page.

If you want the lowest rate, use your AAA card, or AARP card. Same lowest rate as "internet only rate" but always refundable. Not only at BW but at many other hotel chains.