I feel the WF's plight honestly, but rusties can be abit annoying to anyone. Heck I mainly play an elf caster but for some reason when I run Ataraxia's haven those darn things make a beeline for Kalari and I hardly wear any metal save my bracers. Heck the other night one ran right past the cleric who was in metal armor and went straight for Kalari and I was like um what the heck? (Ive made jokes about wearing a mithral chastity belt but that was ridiculous). It maybe could be because I tend to have the spells that roast them alive. That could help WF's to, playing with smart casters who know that holding a rust monster in a firewall, or scorching them till they end up sizzled husks tends to get the job done. I also try to cast stone skin on my WF buddies as well, I didnt know this did anything till one guy I ran with asked for it and helped him abit. With proper support in a group setting a WF can handle a rusty np from what Ive seen. Solo maybe not so much unless they are a caster type, then once again holding them in a firewall works wonders. I dont know if this helps lower level groups but with good stradegy a rusty can be taken down before it gets to the unfortunate WF it wants to snack on.
And I agree with the Stirges it would give me the willies but so do spiders and other critters so bring on the scare, my guildies think its funny when I run around screaming for dear life as it is.