Session cookies appearing where there is no session

This must sound pretty far-fetched, but as far as I can tell, my site is attempting to set a session cookie from any and all PHP pages, even when the page has no calls to session_* functions and where there were also no previous visits to pages with such calls. Where is the setting that is initializing these unneccessary sessions and sending the cookies? I looked for something in php.ini or phpinfo() to explain it, but came up empty. Below are excerpts from a phpinfo() dump. I wondered about that "session.use_trans_sid", but there's no reference to it in my php.ini file (yes, I checked that phpinfo says I'm looking at the correct one) and I also cannot find anything about it in the PHP.net online docs. What does that setting do, and where is it configured? TIA --------begin excerpts from phpinfo()------------ Directive Local Value Master Value assert.active 1 1 assert.bail 0 0 assert.callback no value no value assert.quiet_eval 0 0 assert.warning 1 1 safe_mode_allowed_env_vars PHP_ PHP_ safe_mode_protected_env_vars LD_LIBRARY_PATH LD_LIBRARY_PATH session.use_trans_sid 1 1 session Session Support enabled Directive Local Value Master Value session.auto_start On On session.cache_expire 60 60 session.cache_limiter nocache nocache session.cookie_domain no value no value session.cookie_lifetime 0 0 session.cookie_path / / session.entropy_file no value no value session.entropy_length 0 0 session.gc_maxlifetime 1800 1800 session.gc_probability 1 1 session.name SID SID session.referer_check no value no value session.save_handler files files session.save_path /tmp /tmp session.serialize_handler php php session.use_cookies On On <snip> HTTP Response Headers Set-Cookie SID=0c6a1e4a46c8d9d840ac865d4a9d8e6f; path=/ Expires Thu, 19 Nov 1981 08:52:00 GMT Cache-Control no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Pragma no-cache <snip> -- CC