Yes, but good employers have enough respect for their employees as humans that they want to avoid hiring and then firing someone at all costs. Not to mention,

Yes, but good employers have enough respect for their employees as humans that they want to avoid hiring and then firing someone at all costs. Not to mention, a company that routinely fires new employees after just a week or two would probably get a bad reputation pretty quickly. Unless they're Facebook (which supposedly does/did this in six week intervals), they probably would take a severe hit on the quality of applicants in the end.