All arachnids are venomous except for a select few species such as the Solifugae (sun spiders, camel spiders, etc.); however, most venomous arachnids are harmless to most people.
All the practice in the world will not prevent a bite, though, as the "experts" on free-handling have found out the hard way. It doesn't seem like that's going to sway your opinion on the matter, but I'm not going to to push that further provided that we can agree that this is a handling method that is not recommended by anyone, including free-handlers.
IMO, the best policy when it comes to taking a severe bite from a spider, reptile, etc. is to get the appropriate treatment while ensuring that the media doesn't find out anything in order to avoid creating more bad press for the exotic animal hobby.