Hmmm, Lets see. How many people go just BCs? Tiger-fury always goes BCs and wraiths to close out a game. If the carriers run away, then harrass them with wraiths. Pheonix is right, Carriers can take out BCs, but it doesnt help a lot to keep on running away around the whole map, just go after the base. Terran BC is a bad choice tho, so are carriers. Too many resources. lots of wraiths and scouts can take out capital ships easily, they are too slow. Terran opponents are quite hard to beat with marines, medics, tanks, goliaths and wraiths....Carriers would get killed by the marines, golis, and wraiths... Tiger-Fury usu. goes goons, DTs, and HTs. Psi storm takes care of the pesky marines and wraiths and you have almost dead tanks to worry about, DTs can wipe them out. My friend, Iron_Blood, ranked #2 several years ago, used Hydras, defilers, and zerglings and guardians, and inched his way to the opponents base. Carriers cant stand against this. Zeals and DTs could be produced, but tons of Zergling support take care of them easily.
Pheonix, what im talking about is when the BCs actually break into your base and you have to duke it out head to head with the BCs instead of pulling them back steadily. You are most likely not going to let your base be ripped to shreds while trying to save your Carriers.
Not that I dont like carriers. Its good to attack with a large group of carriers and have a couple arbiters back at the base. Attack with the carriers and dole out as much damage as possible. Once all the shields are gone and the hp on the Carriers starts to slightly diminish, recall them back to your base, use multiple shield batteries, then move up to attack again with almost instantaneously full health carriers. This can be quite damaging. BCs cant be transported or healed as quickly as Carriers, to the BCs disadvantage. Recall the carriers back and recharge again if needed and attack with almost full health carriers again. Most likely, you wont have to recall the carriers more than once or twice. They can rip through a base like none other.