RE: If you're on LinkedIn, and you use a smart phone...

Jimmy Hess wrote: [...]

This may be easier than you think, if remote account access is allowed only using Web-based mail, and company managed mobile devices. Whitelist the cell carrier's mobile network, using ActiveSync.

An IMAP connection attempt from anywhere is immediately suspect.

This assumes good mobile data signal and no use of home WiFi, hotel WiFi, airport WiFi etc... I'm not convinced your proposal is much better than stopping the device from being useful in a significant proportion of the situations it would be used.