Does your agency make you .......

Hello,

I have been a med surg nurse for a few years and have done some travel as well. I signed up with an agency since there were no travel opportunities. I was put on a tele floor and all of my 5 pts were on monitors. I was told I cannot refuse to float. That there is a charge who would "take over" in the event something went wrong. What are your thoughts....................I NEVER had to go work tele in my past jobs when I was pulled. Is this legal??
Thank you!