I think you've got that backwards. The longer the wavelength, the less likely any part of your body is acting like a resonant antenna. A full wavelength at 450mhz (like the "Family Radio Service" radios you can buy at Shadio Rack) is in the vicinity of 12 inches and the higher the frequency, the shorter the wavelength. The shorter the wavelength, the more likely you are to really need a tin-foil hat. Grab the antenna of even an hf (3.5-30mhz - wavelenth from 250ft to 40ft) radio while it's transmitting at 25 watts and you can get RF burns. That's physical heating of your skin. I have personally experienced RF heating of my hands when merely waving them near leaky microwave waveguide (less than 3 watts) or near the edge of a uplink antenna. This is the same thing as sticking your hands in a microwave oven while it's turned on (not likely with interlocks on the door....).
Admittedly, a handheld celery phone only runs 100mw - given some gain in the antenna, it's still orders of magnitude less power than what I've been talking about. However, a mobile unit transmits something on the order of 3 watts which at microwave is enough to feel if you grab the antenna while it's transmitting.
I worked in the telecom business from land mobile radio to terrestrial microwave point-to-point to satellite television earth stations (fixed and mobile) for better than 15 years. I've received well over $50,000 worth of training in microwave transmission systems. I don't have a third eye growing out of the back of my head yet. Obviously, I don't have an irrational fear of RF exposure or I wouldn't have subjected myself to as much as I have. On the other hand, I would prefer to limit my exposure to ANY RF and microwave in particular. I personally would not like to live near a cell tower. I would not like to live near a TV transmitter antenna farm (particularly UHF) and I would rather not live near high-tension power lines. (I personally know a guy who was working on a UHF television transmitter antenna when some dummy down below turned the transmitter on. That guy was never quite the same after that - and everybody in the market he worked in knew it. Granted, he was subjected to HUGE, MEGA, GIGANTOR AMOUNTS of RF radiation compared to a cell phone but the point is he was damaged.)
Until more is known about its effects on people is known, anyone that casually dismisses RF radiation exposure, even if at a low level, is simply being foolish.