well some teams are also idiots and yolo. luck will determine the outcome if you're not certain of the enemies position. but you can't also sit and wait for the enemy so if uncertain of their position, be proactive and reactive. meaning proceed with caution, but proceed - sitting in the back alone, uncertain of the enemies position (at least from what i see in WOT) might turn out to be a slaughter fest, where the enemy team feasts on you! and its hilarious when you see it. they get one shot in the enemy but then get 50 shots back!
it is a split second decision between the both tho, yes, but also, the more you get familiar with the map the easier it becomes to switch between pro and react!
most importantly tho is to have fun! gl&hf!