An adult BP could theoretically strangle a human....IF...that human had no arms or hands to unwrap it. They're not so strong that an average person couldn't pull them off.
In all my years of being a part of the BP community, and in a great deal of research...I've never found or heard of a single incident of a BP actually strangling anyone or even causing anyone to pass out. But they are strong enough to cut off circulation to the brain IF nothing were to interfere with them in the process.