if you go during high season, absolutely!
if it is in a low attendance period, usually not an issue.
3 boys and myself did it as a walk in one time.
only 4 other families showed up.
i think many newbies don't realize that you don't have to have ressies to eat there.
if you see a lot of empty tables, ask the tm is they are full or holding tables for ressies.
if you come a long way or only make family vacations once every few years, by all means do a ressie for spidey.
for the hotel island breakfast, no ressie really needed most of the time.
you can make them if you want to though. if you go when most do around 10ish, it is very crowded then. another crowded time is 9ish.