Yeah, I would agree with no I think. And no, it makes sense - I understand what you mean. It does make a lot of sense really as the weapon or whatever other item just cannot exist in that other world, I guess? 

Maybe part of it is that there is a way to get it so you can bring technology/magic from one world to another, and that's what the 'bad' guys are trying to work out (as one of many things)? I don't know, maybe that wouldn't work... Crazy mixing of tech would be crazy. And yes, I think the same thing would go for cell phones. Although you just wouldn't get signal in the fantasy world if one survived the journey. Although some things would obviously survive the journey (clothes, for one, I would hoped)