Yes, this is a danger. In 2011, Iran probably goofed on a US drone's GPS (
https://en.wikipedia.org/wiki/Iran%E2%80%93U.S._RQ-170_incid...) in order to get the drone to land where it wasn't supposed to (in Iran). Further, the technology to do this is almost mainstream. Surveyors use something called "differential GPS" to get very accurate locations. I bet that differential GPS transceivers could be hacked to override, rather than just correct, regular GPS receivers.