I am not open about it. A few of my female friends probably have an 'idea' about my affinity for tickling feet. However, admitting to them a fondness of tickling could lead to them thinking me tickling their feet is sexual in nature, when, in most cases, its not. Its just fun most times.
I've actually been called out by some about it (only one friend called me out, but I brushed off her question), and I've found that different people take the truth different ways. Some ask questions like, "Why do you like feet?" or, "Why tickling?" I turn it around and ask them what feature they like on a guy. Most don't say, "The penis" (lol) so its an easy way to say, "Well, you like a guy's arms, chest, eyes, etc....I like a girl's feet the same way." The same with tickling...ask a girl if she likes to hug or cuddle, and its in the same vein.
I agree with many, and avoid the term 'fetish' as, in its classic definition, I don't have a foot/tickling fetish. I don't NEED feet or tickling to perform sexually. I just think feet and tickling are sometimes a turn-on (just as a girl may think a massage is a turn-on...doesn't mean she gets hot when she goes to the spa).
I am not even open about it with my GF. I put her in the category of having an 'idea' about it, but never been discussed. She does know I think pantyhose are sexy, but that's as far as it has gone.