The most famous "tool" used in this field is the drake equation. If you cut the product to the fraction of those planets, fl, that actually can develop life, y

The most famous "tool" used in this field is the drake equation. If you cut the product to the fraction of those planets, fl, that actually can develop life, you have a much higher probability than the one you get with the full equation, or by accounting {fi} or {fi,fc} too. So from a strictly statistical p.o.w. that's something more likely to happen. What has to be considered in the evaluation of the possible threat is that the way our brain is used to think, the interspecific competition model, the r/k strategy are all based on two assumption: limited resources and competition. Supposing travelling in space is something difficult/time-consuming and supposing each planet may tend towards the emergence of a dominant species, those two constraints would be relaxed: hence the coexistence of not directly interacting species may be circumstantially possibile.