I dont think this is really a problem in PA..
even not with small planets that get bashed coz altho they get plenty of incs every night from there fellow small planets (that gain little from the attacks)
they dont get mass incs.. (its more like they get 3 incs EVERY night
)
and theres a bash limit of 40%..
And its a valid (not often used) tactic for normal allies..
It can balance things out a bit for the allies.. its a necessary evil sometimes
and its alot of fun to do