Pre-Climbing Stretching?

This site has lots of info on training for rock climbing. Including this:

“Here’s a good bet on a better pre-climb ritual, for both competition and training.

1. Get a general warm-up. Think hiking to the crag. 10-15 minutes of nice, easy activity. Sure you think it’s a waste of time now, but wait until you are 50. You’ll wish you’d listened to me when you’re hanging out at Mt. Rainier instead of Hueco Tanks.

2. Move to a more specific warm-up. Grippers, hangboards, easy climbing, pull-ups. Whatever it takes to get good and ready to climb. This should take about 10 minutes.

3. Ease into it. Sure we’ve all heard about the guy who “never warms up” or sends hard off the couch. That ain’t you. Here’s a quick test: Were you in “King Lines” or did you pay to watch it? If the answer is the latter, take it slowly.

So dump the pre-climb stretches, stretch all you want afterward, get real with your warm-ups, and realize that if you are “training” but have not improved in the past 6 months, you’re doing it wrong.”