Look, this has gone paranoia. The age of magic, SEO and making money at home should already be over, there are no secret sauce to a hot pie everyone wants a piece of. I found no problem giving free consultation (within my capability) to anyone, interviewer, like-minded techies in user group or new comer who wants your seat with minimal effort. Success coming from quality of a person NOT knowledge encapsulated within one’s brain!
If a company able to benefits by your “free consultation”, then it’s their loss not to meet your demand and hire you.