Buying Used Equipment

in CCNP
Friday, two Cisco reps came to work to talk about our equipment. My boss 'showed' them my CCNA Security book and I showed them my CCNA cert. 
Anyway, somehow we talked about home labs and one of the reps said not to buy used equipment (such as from ebay). Her husband is in Canada right now fixing a problem there. Apparently, people put malicious code in the routers and switches that is very difficult to find. Also clearing the flash is not enough.
Has anyone else heard about this?
Thanks,
es

Anyway, somehow we talked about home labs and one of the reps said not to buy used equipment (such as from ebay). Her husband is in Canada right now fixing a problem there. Apparently, people put malicious code in the routers and switches that is very difficult to find. Also clearing the flash is not enough.
Has anyone else heard about this?
Thanks,
es

Comments
It is possible to change the ROMMON on a router/switch to do something potentially malicious but it just isn't worth the effort. You can do plenty of other easier and quicker things if you want to piss people off or cause havoc.