Cabinets -Build In Flex?

the only cabinet squeak i've had was a little hard to track down. in addition to bolts through the cabinet backs (into rivnuts in the walls) i have a couple of angle brackets that connect between a rivnut and a cabinet sidewall. it turns out that the junction between the angle bracket and the wooden side was making a huge squawk (like a parrot screeching!) when i'd hit a bump. it turned trips down a concrete-jointed interstate into quite the pleasant experience. ;-) i fixed it at a rest area by simply putting some masking tape between the steel angle bracket and the wood sidewall. hasn't made a peep since. (this was near the end of the passenger-side cabinet that protrudes into the slider opening. i think there's more flex in my cabinets there than elsewhere because there are fewer attachment points.)