1994 Honda Accord CV Joint Boot Tear after 6 months

I had both drive axles replaced in June '07 after hearing knocking/clicking noise when making turns. This was done by, let's call them "Mechanic A". In December of '07, "Mechanic B", when performing a routine oil change, informed me that the CV joint boots were leaking grease and need to be replaced. I then had Mechanic B proceed to replace them. After beginning the work, they informed me that the inner boots both had tears in them and had leaked enough grease that the drive axles need to be replaced again. They showed me the torn boots and they were clean tears, almost like they had been cut. I can't imagine a rock or something from the road making nice clean cuts like that. Is it possible that the boots could have been inadvertantly damaged during installation when the drive axles were replaced the first time? Or that the boots they installed were defective?