Venue is for party's convenience

In civil proceedings, venue is procedural, not jurisdictional, and may be waived by the defendant if not seasonably raised either in a motion to dismiss or in the answer.[1] Section 1, Rule 9 of the Rules of Court thus expressly stipulates that defenses and objections not pleaded either in a motion to dismiss or in the answer are deemed waived. As it relates to the place of trial, indeed, venue is meant to provide convenience to the parties, rather than to restrict their access to the courts.[2] In other words, unless the defendant seasonably objects, any action may be tried by a court despite its being the improper venue.
[1] Marcos-Araneta v. Court of Appeals, G.R. No. 154096, August 22, 2008.

[2] Rudolf Lietz Holdings, Inc. v. Registry of Deeds of ParaƱaque City, G.R. No. 133240, November 15, 2000.