In reply to hugohermann:
It's pretty unusual to pull a large flake off an established problem, but big drops onto mats (and the occasional miss) are inevitable, and sooner or later one is going to hurt.
Of course you can set the rules as you choose, and it's entirely possible to stick to traverses, low problems and benign landings, but to see it as safe because of the presence of mats would be a mistake. Climbing walls see more mishaps in bouldering areas than anywhere else.