Amp techs are often musicians themselves so more often than not, you get a lot of the same, fucked up personality traits to go along with them. I won't name names but I believe there's three basic types :
a) honest guys who are clear and upfront about everything, and will bend over backwards to please the customer, especially if the fault or issue lies with themselves.
b) dicks who are rude assholes who let you know about it within the first 5 seconds of the conversation or first few words in an email. Not pleasant to deal with, but these guys are not thieves and the customer ultimately gets their product, despite some frustration along the way. For better or worse, the customer should at least be able to easily ascertain what they're getting into with this type of person.
c) guys who put on a good show, try their best to give the illusion they're of the type a personality to lure customers or make fake friends, but quickly do a 180 and turn into a type b or worse, by never fulfilling orders and keeping the money, or lying, or going back on their word, breaking promises, etc. Its this type that you really have to watch out for, but its almost impossible because of the unpredictability and lying that these people are all aboot.