http://www.securityfocus.com/brief/134
Interesting story about the first case (i am aware of) where a company has required all employees who access a secure area to get a verichip implant.
Its not good to think that some kind of personal data can be read off you by scanners where ever you walk. Especially when it would appear verichip tags could possibly be easily cloned with the right equipment http://cq.cx/verichip.pl. If so this could be a bigger security hole than the old card systems used by the company in question. It is possibly a mistake by the company to rely for security purposes on such a new technology, especially as when questioned they where unaware of some of the security issues around the devices.
A would be ID thief would have to get within a foot of the subjects implant, due to the range of the chips. I personally think that some one who had thier mindset on such theft could easily do this, i often have people within such a range whether i am queueing at a petrol station or in a lecture.
Also with the constant moving of technology and security how many of these implants would an employee be expected to have over their working life. Every couple of years as one item becomes obsolete are they just going to demand employees get another implant, and how many of these things are people going to end up with in their bicep.