I'm surprised nobody has touched on this but the scoring format used has a lot to do with whether or not safeties are even worthwhile.
In a typical BCA team event, each rack is worth 1 point and you play to a set number. In this format, safeties often times make sense.
In other tournies (ACS for example) they may score each rack by the number of balls pocketed. So the winner will get 10 points and the loser will get however many balls they pocketed. So if you manage to break and run a rack you will win 10-0 (or 10-1, 10-2 if you happened to pocket one or more of your opponent's balls on the break), these 10-0 scores are huge for your team. This changes the value of a safety quite a bit.
Now say, you are in the middle of a run out and screw up and you have three of your balls left on the table and the eight. What do you do? If you elect to play safe, you may never get another chance to score these balls. So you're effectively leaving points on the table. This can be bad in this format. This is why I think a lot of teams just throw caution to the wind and constantly go for the out. Even if you only have a 25% chance of getting out. The reward is a 10-0. If you don't get out you are only going to lose 10-7. Now if you play safe and get out moved, which is likely against a good player since they have all their balls to play with you may end up losing 10-3 or 10-4.
So, the scoring format has a lot to do with it. I like the ball count method. Players try to run out more and this really speeds things up.