Warranty issues yes. Also notice the orientation of the stock fans... You are going to want something similar most likely as the fans are blowing across the chassis so they cool down the little ASIC chips. It will certainly work the way he's doing it but he's turning a 1U switch into at least a 2U switch which is pretty dumb... especially when he's got in in a rack. with servers that are likely much louder.
If you do an exhaust fan I don't think it's going to be all that effective because he's going to be almost right up against the switch mainboard. Stick your hand on the back of a fan and notice how much it's power is decreased... it'll be the same on the switch.
For me this is a non issue as my SRW2024 is in the basement with my Endian firewall... don't really care how loud they are, no one will ever hear them.




