Doing this is probably not a very good idea - Getting lots of configure events from the server can be problematic, but that's what _NET_WM_SYNC_REQUEST is for.

(However, some window manager *cough*theoneiusedtomaintain*cough* don't support it very well).

Processing certain configure events could have side effects that you might skip by not processing them. So its better to just process them. There could also be upcoming events in the queue whose processing might assume that a window is of a particular size.