Tongs are simply a tool that can be used in circumstances that require them, they have the potential to cause harm, particularly cheaper versions. We train people to use them, on rubber snakes, to get the feel of them, to enable a person to make a decision for themselves. They can cause harm and are NOT the solution to snake catching. I have used them on occasion on wild snakes, as Jono described, having no alternative on hand. We will only use and sell Gentle Giants, I have found them to be the safest in my opinion.
I have not heard of injuries with hooks, but certainly with pinning and tailing. It comes down to each person, each job and personal preference. Most people that I train will tell you they prefer hooks and tailing above all else!