I am probably the biggest braking fan on the web but for most skate race pack crashes brakes are not likely a good tool. If the pack is going to crash brakes are likely to simply make things worse. The best tactic is to avoid by going around things and/or jump over stuff. This is an area where agility drills on skates are a real good idea.
I believe in develop ALL my skating skills as much as possible. Jumping stuff is very useful if you can do it instinctively. Even though I like a heel brake a normal T stop is still a good way to control speed mid way through a turn (so you need to be good with both legs). The front T is useful in some conditions but generally it is more of a "trick" stop rather then a bread/butter move. Even Eddy is sketchy with the front T on grippy roads with new wheels. Eddy's primary stopping tends to be slalom stopping. Using a slalom is good on your own but not so good in a pack and really not something you want to do in traffic.
I use a heel brake stop when I need braking power but in a pack you need to think about what is going on behind you and generally for pack skating or even cycling stopping is the most dangerous thing you can do. To avoid a crash, the best method is to find away around or even over the problem and keep moving. If it all goes south, falling well can help a lot so doing some tumbling drills is useful so you know how to fall without getting hurt.
For a Weinfelden, I don't know what happened and I am sure that the skaters had good agility. Sometimes as has been said @##$@ happens and you can't avoid the crash. For other times going around stuff is the best way to go. On rare occasions in panic situations a brake is useful and it is an option some skaters will pick (not for everyone but I personally like having more options rather then less).
Remember the world is dangerous so make sure you are as well prepared as possible. Skate safe, have fun!