idk man one of my cfls shattered wen i jus had it close to another light.... not shatterd but i tried taking it out and it just broke... all i can say is be careful
its best for them not to touch because the light bulbs do vibrate while they're turned on and it could cause one to break
It's easy enough to make sure they don't touch, so make sure they don't to be safe. CFLs can be damaged by excess heat.