Unless an employment contract has a specified term (the military is the primary such example), employment is at will on both sides. An employee can quit without notice, demand a change in pay or working conditions, or otherwise insist on renegotiating or terminating the relationship without notice, although two weeks notice is polite and traditional. Would you eliminate that option?
Of course not. Did I give the impression I would?
I am an employer. I hope I am successfully balancing my business's needs with consideration for my employees I always hoped for from those who've employed me in the past. This employer's problems stem from his apparent unwillingness to do so.