Usually not a problem unless your airlock is overfilled. I would go with plastic wrap myself but mostly because there's not enough headspace for the airlock in my fridge and I don't have caps for most of my carboys.
Originally Posted by Robusto
"The main ingredient needed is 'time' followed closely by 'patience'." - The Bishop 2013
"Good grief! If someone wanted to murder you, all they would have to do is ship you a 55 gallon barrel of honey and watch you document working yourself to death!" - Vance G
"When you consider that laziness and procrastination are the fundamentals of great mead, it is a miracle that the mazer cup happens." Medsen Fey, 2014
"Sure it can be done. I've never heard of it, but I do things I've never heard if all the time. That is the beauty of being a brewer!" - Loveofrose, 2014