IF there are a lot of lines there the odds favor an easement exists someplace ...and utility lines may have broad easements of necessity . I'm not saying it's absolute ...I've had neighbors discover a line pole in totally wrong place and underground lines in totally wrong or unpermitted locations ...and I worked for a power firm which purchased a small operation with totally screwed up and missing records ...and some lines strung literally with Coke bottles as insulators !!
You can demand proof...but odds favor it's there someplace.