it's been in my experience that administering IV fluids ( normal saline ) at a t.k.v.o rate is not harmful and infact , if they need to admin T.P.A ( clot buster ) well they then have an IV access already established with your line and fluid running. I believe that as long as doing the line isnt delaying transport then its an acceptable practice and usually the nurses are thankful a line is running for them upon handover in the ER.
An intravenous line is inserted to provide drugs and fluids when needed at the hospital anyhow.