not totally accurate
you can probe another member when you have espionage tech 2 and a probe... if the member has espionage 2 or lower it will display all details about their resources, fleet and defence (the only real interesting bits)
if the other member has a higher espionage tech level than you - say 3... it will only display his/her resources and power output... thats why i sad its useful to see their power output, if its 2000 then you know they are advanced and you know for a fact they will have defences and some fighters etc.
as long as you have a higher espionage tech than the person your probing it will display all details, if you dont, you only get limited information

, Matt