You can’t always tell if employees or co-workers are considering a career switch, but if your top-performers show these outlandish signs, it’s time to start taking applications.

There’s nothing wrong with scoping out the competition or making sure a resume is up-to-date, but when people start behaving like this, odds are good they’re going to abandon your company faster than the Titanic:

1. During sales demos, employees explain that although it’s not scientifically proven, they suspect your company’s software contributes to global warming.
2. Their Facebook/MySpace/Linkedin profiles have more detail than a string of DNA.
3. On casual Fridays, they show up wearing “Monster.com Job Fair — Summer 2008″ t-shirts.
4. They ask IT for help downloading the client contact list to a portable USB drive — the flashy new one, emblazoned with your top competitor’s logo.
5. They’ve updated their company e-mail signatures with a personal e-mail address — financepro4hire@needajob.com.
6. During cold calls, they refer to your company’s cutting-edge product as “that $&8# we sell.”

The signs aren’t always as clear as these — how can you tell when co-workers are planning a move to a different company? Share your comments below.