^ The problem with that, though, is that there are some cheats that are unmistakable -- jumping walls, shooting through walls, sending chiron through walls, glitching into castles, destroying repair points, etc -- but there are also many things that people cry cheats on that, most of the time, aren't even cheats. Then, of course, there are things that certain people consider cheating, but the majority of the community doesn't see it as cheating.
For example, person A kills person B, person B calls hacks because person A attacked 5 times in a second/was constantly immune/ported around/othercommoncomplaintshere. A lot of the time, though, less obvious things like these are just the result of RW's shoddy coding -- while it may look like someone's hitting me with 5 scout skills in a second or less, that's not what they saw on their screen. There have been many times where I've used Rock Protection, then been hit by a skill or two, and been one or twoshot through RP because of client lag. Same thing happens with immune foods all the time. Sure, some people in these situations could be hacking or whatever, but is there a way to say that definitively? No.
That's why I hardly ever call cheats on anyone in siege. Only time I do is if someone did some of the obvious things as mentioned above, which aren't common to see from reputable guilds. It would suck to see a guild's reputation get destroyed, too, if someone were accused of doing one of the more obscure things that could really just be siege lag.
With your idea, someone could call one of their guildmates a cheater, and even if that guild knows that person did not cheat and does not ever cheat (and therefore won't kick them, because they have no reason to) ...you have just destroyed an innocent guild's reputation in siege.
I'm as eager to eradicate exploiters from siege as the next person, but the truth is that something like this would do more harm than good. There's enough drama around these forums about people calling hacks when there aren't any. We don't need more. Runewaker just needs to fix their crap.