Most aircraft movement in and around DZ's is generally co-ordinated between the pilot and the DZ control or tower (if there is one). DZ's are also notamed and are marked on charts etc.
Unfortunately not all pilots bother about Notams and not all aircraft are fitted with radio's, especially gliders (apologies if i am wrong). Every year, more or less, there is a collision between Skydivers and gliders throughout the world.
On the other hand, the jump pilot is given the all clear for the skydivers to exit the aircraft from the DZ controller who is meant to be the skydivers eye's on the ground.
Bearing in mind, skydivers are heading toward the ground at speeds between 120 - 180 mph depending on what they happen to be doing at the time, different manouvers mean different speeds!!
Now, the answer to your question is yes, they can look around, but when you have approx 60 seconds in freefall, thats from 12000ft, It isn't really a long time to look out for aircraft that shouldn't be there in the first place. I am also a skydiver with a 1000+ jumps
