Question on Raiding etiquette of p99

[Tasslehofp99]

Lets say guild A and guild B zone into plane of hate or plane of fear, both with intentions of clearing trash for armor drops. Guild A has more members in zone, and arrived first, yet guild B still intends to gather/raid in the same zone. Is there any kind of rules against this? Two raids in a row now we had other guilds in zone clearing, meanwhile theres been 2 other occasions we backed out of a zone because another guild was already there out of respect. So...are there any like rules on this server or like unspoken understandings? [You must be logged in to view images. Log in or Register.] Just looking for some clarification is all for future reference.