using multiple agencies???

What benefits? Bad health insurance is the only benefit you are likely to receive.

Recruiters may respond in a couple of ways if you tell them you are working with other agencies, and usually to your benefit. They may stop working, and who wants someone that unprofessional? That scenario may also be an agency that is taking advantage of new travelers, and once they learn you are shopping around, that is the end of it so why work? Or they may work harder to get your business when they find out they have to.

So if you don't work with more than one agency, you will never find the best recruiter fit for you, which happens to be the best correlation to success as a traveler. You will also not maximize your travel assignment options, nor will you ever learn what your fair market value is in a given location. Which also means you have lost most of your negotiating power.

Guess which way of travel that I am a fan of!

I have 2 agencies. I took 2 assignments with Fastaff and now I'm on my second assignment with Flexcare. I didn't tell my Fastaff Recruiter anything when I took my first flexcare assignment. I just didn't call her back. I don't know if that was unprofessional or not but she still sends me emails of hot jobs every once in a while. When I see something I like I will call her. As far as the benefits are concerned, it's no more of a hassle than filling out some paperwork which you'd have to do anyway. For me taking on a second agency was no big deal. It always comes in handy to have more than one agency. That way you have more job options and more competitive pay. I call it "cheating" on my agency but most travelers I talk to have more than one agency. I think it's the norm.