Dictionary definition: "accept the authority, principles, or policies of a particular group, especially under pressure." By this definition, this is exactly what many doctors are doing, and it ties in perfectly with the OP's question.
Glad to see lee’s ghost has been corrected regarding the (proper, in this case) use of ‘toe the line’.
Well, apparently that’s the modern interpretation. It come from this...
https://www.youtube.com/watch?v=20M_teQf-l8