"People"? What "people"? "People" with a deep understanding of the natural world and plant biology? Or would these be the same sort of "people" who claimed that we were about to enter a new ice age in the 1970s when in fact there was absolutely no scientific consensus suggesting such a thing?
What happens (at least) in certain instances of companion planting is well understood as far as I'm aware. Planting in accordance with the phases of the Moon has been debunked frequently. I believe many fans claim it's to do with the way that water behaves under the influence of the Moon's gravity (like it does to create the tides, right?) whilst ignoring the fact that water in contained spaces such as plant cells will behave completely differently.
Perhaps dogs just like that spot. What have you done to discount any other plausible explanations? What other explanations have you even considered?
Without accurate and specific documentation of the test, that's really not an answerable question.
Which is therefore subject to whatever biases, prejudices and errors of judgement that affect you. As I've posted before, one of the most important parts of testing a hypothesis (that dowsing works, for instance, or that "energy lines exist) is eliminating the issues that humans unwittingly bring with them.
James