It is an involuntary gasp reflex followed by hyperventilation. These affect the ability to breath normally and can cause the breathing in of water that can result in drowning. Typically, there is one gasp reflex. The hyperventilation can last 10 to 15 minutes. It does not occur in all cold water immersions.
Cold shock can complicate a rescue.
The gasp reflex can interfere with ones roll due to the involuntary breathing in of water. The hyperventilation will prevent a person from holding their breath for very long complicating the ability to do a reentry and roll. No, but it is meant to help educate people on the dangers of cold water. This will hopefully result in the people who do paddle in cold water to realize the risk they are taking and to take the proper precautions.