My mother still spells the short form of 'refrigerator' as 'frig'. At least she did when I was a teenager and I have no reason to believe she has changed her opinion since then.
And the reason I noticed it is simply that it is open to misinterpretation, just as Faldage says. 'Frig' with a hard g sound as opposed to a 'dj' sound (ie rhyming with pig rather than bridge) has an entirely different meaning in British English at least!!!