The biggest tactic I've seen is their inability to be consistent. In 2 years, I spoke to 3 Oracle reps and received vastly different quotes for the same hardware, features, processors/cores, etc.
Definitely! We actually dropped one vendor because it was all ex-Oracle salespeople, and their negotiation tactics were outrageous. They tried to hold us over a barrel and instead we made a major platform change in six weeks just so we could tell them to f-off.