Subversion 1.5 added an interactive dialog to merge remote changes with local changes. This dialog can be disabled with --non-interactive.
Created attachment 174430 [details, diff] subversion-eclass-non-interactive.patch
--non-interactive would also disable SSL certificate prompts. --non-interactive could be used only with another option which probably will be implemented somewhen: http://subversion.tigris.org/issues/show_bug.cgi?id=2410
Maybe --accept=postpone could be used.