That would be one case where it would be very handy to let go quickly.

Then a man is likely to get his hand caught, and if he can't let his rope go free he is likely to lose a finger or two.
"Our vaquero is trotting along with his rope hanging at his saddle bow or fastened behind him.

He sees a deer or whatever else he wants to catch, and grabs his rope with the left hand if he is a right-handed man, though a man to really excel in this business should be ambi-dextrous.

A right-handed man can, under ordinary circumstances, rope a steer; but he has frequently to turn his horse to gain a good position.

Now it sometimes happens that your horse is in a position where you can't turn; then it would be awkward, unless you could throw with either hand.