Hostilness? Enemy Making?
Phase one: Guilds have a feud. Now they are enemies. Phase two: One of the guilds attacks the other. Some glitching is done, the other guild retaliates by fighting fire with fire
Phase three: Both guilds accuse each other and attempt to have them caught cheating, therfore more work for GP's

Conclusion: This is a terrible idea. Just because guilds congradulate each other on fort hours it doesnt mean they have more or less rivalty. Hostileness is just asking for cheating to happen. Respect doesnt mean theres going to be any less rivalty, just less cheating and keeping thhe game more age friendly... Nobody wants all this hate going around.