Sorry that happened to you, but that is just not good advice. Trying to fool them at all isn't advisable, and your suggested scheme involves multiple levels of deception - lying both about what you did and what your intent was, trying to appear eager to help when you're not. Most normal people are not such skilled liars, whereas border agents are always on the lookout for deception.

Also "just say that's what you normally do when entering border control" goes against the image you're trying to create.