A financing statement should not suffice as evidence of a security agreement because a secured party may often wish to pre-file a financing statement, that is, file the financing statement before and in anticipation of reaching a security agreement with the debtor.  If a secured party pre-files it can then wait, before executing a security agreement, a period of time equal to the known delay between a filing office's receipt of financing statements and the filing office's indexing of received financing statements.  If negotiations with the debtor proceed successfully, it can then search the UCC records just prior to executing the security agreement.   The search could conceivably reveal a filing just earlier than its own (a filing that, because of delay in indexing, might not have been revealed by a search on the day it had pre-filed).  It can then terminate its further dealings with a debtor who had failed to alert it to transactions with another creditor.  A search that reveals its own filing but no other earlier filing confirms the debtor's honesty and, under U.C.C. 9-322(a), assures the secured party of a priority, from the date of its pre-filing, over later filed non-purchase money security interests in the same collateral.