If counting the number of businesses that will pay an employee for the two weeks, even if company asks them to leave before the two weeks are up (after employee gives two week notice), then you are probably correct, but I would bet the majority of the 5,000 largest companies in the US will pay them for the two weeks if they ask the employee leave sooner. The reason is that most of these companies have a policy that if an employee does not give two weeks notice, they might not be eligible for rehire. In some cases where such a policy exists, if an employee gives two weeks notice and the company tells them they must leave immediately and will not pay them for the full two weeks, the employee "may" be eligible for unemployment insurance benefits during the two week period. And certainly, other employees are going to hear about someone not getting paid for two weeks if they give two weeks notice and are asked to leave immediately, and that can have an undesirable effect on future resignations if the company generally wants resigning employees to give two weeks notice.
But in cases where it is likely that the resigning employee is going to compete with the company in their new job, a company wants to sever all relationships as soon as possible and not pay them for two weeks, and that sounds like the case here. The situation might also be different for hourly employees where the company has plenty of other people doing the same job that they can use to backfill the position and don't really care if employees give two weeks notice. It is never a good idea to give four weeks notice in the US, because that is not traditional or expected. If the company wants more than two weeks notice, let them bring that subject up.
