I think people have forgotten what the prefix "pre" means. It means to do something before something else happens. For example, precaution means to have caution before something happens. But that is not the way it is being used anymore. Just a couple of my personal pet peeves:
Pre-board: You hear this at the airport every time you fly. But you cannot get on before you get on. Now they could use it like this "we are going to begin our pre-boarding procedures" which means telling us stuff, but as soon as people begin getting on the plane they are no longer pre-boarding, they are simply boarding. It's incorrect usage.
Pre-assembled: "This item comes pre-assembled." Either it's assembled or it's not. The only way it can work is if it's already assembled and then you have to take it apart and assemble it again, or do something else with it, then it would be pre-assembled. But why would you ever need to do that?
Pre-drill: This is used all the time in directions and DYI shows. How do you predrill a hole? It's either drilled or not, because it's not like you are going to drill it again. What they want to say is "drill the hole before trying to put in a screw", or something similar. Now it might be argued that this might come close to the understanding of "pre" but it is totally unnecessary. Instead they should simply say, "drill a hole then put in the screw"
Pre-heat: Like with predrilling it could be used to mean, preheat in preparation for cooking, but I still think it's an incorrect usage as well as unncessary. Instead the instructions should simply say "heat oven to 350° then insert item." Again, it's either heated or not, you can't do it in advance of doing it.