First off, the authentication issue is real. It's also something that has largely been solved by badge readers and integrating them w/ SSO solutions. Everyone has a badge on anyway, and if you can make the login process fast, they won't have so many problems with using them on their rounds as they already use them for all sorts of access situations.
Clinicians are quite possibly the most mobile users I've ever dealt with. You either have them lug a client around with them (tablet etc, usually terrible for EMR use) or you have fixed stations in each room and in common areas etc. We discovered that VDI was a fantastic solution to the mobility problem: users have an open session on a system in a datacenter somewhere, and they can connect to it in a couple seconds by waving their badge in front of any terminal. By reducing the time-to-access and leveraging existing access control tokens you can usually get the user community on board with not trying to circumvent things.
Another thing that this paper notes and which I witnessed in person: clinicians making rounds tend to take notes in their head and then commit whatever they think needs to be written down in a batch at some later time. I watched a doctor engage with a dozen patients and then head to a PC to take notes. Doctors pride themselves on being smart people, but I harbor some serious doubts about the accuracy of this approach and I can't help but shake the notion that the first patient they saw might not have all of the pertinent information recorded an hour or two after the exam.
Finally, as an overall generalization, doctors don't like being told what to do or how to do it, and that goes double for computers. They don't care about your needs to maintain a secure IT platform and will do anything in their power to circumvent anything that they don't personal feel is necessary. Better to engage them early in the process, figure out their patterns, and learn how to work with them because going up against them is likely to be a losing battle.