That works in the vendor's favor in the short term, but can screw them in the long term because you get staff who go the extra mile to avoid the vendor in the future, including structuring requirements to avoid them.
For example, by experience and gossip I know Wind stream has awful reliability, but they handwave that away. By including a requirement I knew they couldn't meet (dynamic E911), they were knocked out of a 200 site VoIP RFP early.
But isn't that the whole point of lying: to the less technical manager (often the only person whose view matters at major customers), the status board saying "up" means the problem is the sysadmins, not the vendor.