I've always been an advocate of not touching gloves before a fight. I don't even give fist bumps in fear that someone might take it the wrong way (like Fox News). Touching gloves at the beginning of the round is the only time in MMA in which two fighters can come in contact without the intent of cutting your opponent's consciousness short. It's usually a sign of respect, unless you fake touching gloves only to punch your opponent in the face shortly after.
Check out what happened in Absolute Adrenaline Platinum in Bournemouth, England last week when one fighter decided to fake touching gloves only to be knocked out by karma seconds later.