This is an excellent example of how science should not be done. Let's just keep one foot on the ground,do a thorough examination of the surface of Luna,and maybe we'll find something other than a coke can and an American flag. To begin the whole process by saying "we're looking for evidence of extraterrestrial beings"...is what I call unhealthy bias. Especially,as has already been noted,we don't have the slightest idea of what we'd be looking for.
(perhaps looking for aliens is the only way to get people interested in any survey at all).