Warrior guilds should all the noded (but some aren't). Last time I checked the administrators are on a node in Landing and Icemule, but not Mist Harbor. However, node or no node, you'll a lose huge fraction of your normal bonus experience if you help someone with partner reps on an empty mind with a multiplier running.

In practice I reckon doing partner reps costs me about 10 experience per pulse per multiplier on average, but do it starting with an empty head and it might be triple that. Thats really when you want to turn the experience gain off. OTOH I once got an RPA out of doing it and 50,000 bonus exp compensates for quite a lot of pulses at -10/-20.