Not a good financial decision.
Besides, when you leave your job, you could roll a 401-k into a Self-directed IRA which you could then use to buy real estate, a business, etc...
You are not forever limited to just stocks.
Also, if your employer matches any %age of your contribuions to the 401-k, then you are passing up on immediate returns.
That's my US$.02
Besides, the stock market is safe if you have a long term time horizon and don't get caught up in chasing fast $.
Just do your homework before you invest.