It's a pretty dumb way to do it, as webmail is not secure. Some of the services have gone to SSL connections, but there are ways around that for people that aren't careful.
The truth is: I don't know why anyone would want to check personal email on a work computer. You can do everything you want on a personal cell phone.
In secure areas that deal with classified information personal cell phones are not permitted. There are electronic gadgets which detect cell phones in case one "forgets" that he has it in his pocket.
Hopefully Homeland Security is mostly in a classified area.