Having lived in a tourist impacted area for many years it was well established that Labour Day weekend was NOT a huge travel weekend.
Most people seem to pack up and head home ahead of the weekend in order that they are well situated for the commencement of school. In some U.S. States I believe they start school even prior to the traditional Labour Day, Canadian commencement date.
This is anecdotal information to be sure but would not be surprised if these factors extend to the stock market where people are settling back into the "traces" for the "fall charge".
Onwards and Upwards.