My :twocents-02cents:
First off, the fellows who blurt out "show feet" in public chat AREN'T foot fetishists, they are reaction fetishists. They have discovered over time that most models, particularly new models, will simply giggle and show feet upon request because at first the model finds the request quite charming (particularly when weighed against "show ass bb"). The "show feet" crowd just wants the model to stop everything she's doing and briefly focus her attention on their one request, it has nothing to do with feet and everything to do with attention seeking. That's why they don't tip, the thrill is in getting the model to dance like a goddamn monkey for no money- they have zero preoccupation with feet.
From my experience no genuine foot fetishist is stimulated by a quick flash of feet. I have size elevens (6ft tall) with brilliantly wrinkly soles and dexterous toes that I can make move independently of one another, I count among my circle of friends a number of genuine foot fetishists and not ONE of those relationships ever began with a public request. Like all fetishists, foot fetishists ASCRIBE VALUE to feet and, like all fetishists, foot fetishists are very SPECIFIC individuals. There is a colourful tapestry of foot fetishists in the world, some like toes, some like toe sucking/licking, some like wrinkly soles, some like rough heels, some like toe nails, some like foot jobs, some like toe wiggling and any combination of any of these things with specific proclivities against many of these things. A 30 second flash of footsie dancing across the screen doesn't "do it" for them.
Fetishists are often very empathetic people who would never presume to disrupt a models room to satisfy their very specific and personal proclivity for a 30 second flash. They know their needs are unique, they know their satisfaction requires investment and they're more than happy to compensate a game model to provide the required service. Genuine fetishists are often the most wise and respectful members of this chat community, their desires are specific and require an adult approach to the topic, not a few dollars thrown at an otherwise preoccupied and uninvested playmate with the expectation all needs will be fulfilled without prior discussion and detailed description of what the expectations are. Fetishists aren't willy-nilly people, they know who they are and what they're looking for and typically act accordingly.
My recommendation to the OP: be a great deal more specific in your tip notes as to what you're looking for. "May I please see your lovely feet?" will get you little more than a flash as it's impossible for the model to know what specific action you're looking for. "I would be thrilled if you scrunched up your soles and wiggled your toes towards the camera for 30 seconds" will get you where you need to be. You're a foot guy, you know what you want, ask for it! That will help you deduce which models are game and which models are lame. Leaving the choreography up to the model in hopes she'll fulfill your particular desires without knowing what they actually are isn't going to be productive for you and isn't going to magically reveal your perfect foot playmate either. Without specific direction you're only ever going to get a 5 second footsie flash, not right-minded model is going to magically provide an A-game under those totally vague circumstances.