xjack:
Thanks for your concern and interest. I realize that the target device will only take in the current it requires and the supply will have plenty of overhead. My concern is on the quality of the power regulation components on the USB hub PCB. If it is a 7 port design, it should require 3.5A to the ports + 0.2A to drive the hub chip + other SMD devices present on the PCB. If the hub of interest is a decent design, there should be no issue as the current blocking diodes on board the PCB should protect the hub in an over current situation if a device that was plugged in was out of spec.
If the quality of the components on the hub PCB was of lower quality, then there may be a potential of premature failure due to the components being pushed continually to the maximum. Since the power supply is robust, it will have no issue supplying the required current; rather, it is the ability of the hub to be operated reliably at continuous maximum load.
Perhaps I should have stated it as the supply will keep pushing the required current; however, the hub may prematurely fail due to continuous stress.
I am very interested in the results of this experiment and I am looking for reliable USB hubs for continuous operation and I am in the process of designing a similar USB hub "farm" to plug in a large quantity of USB mining devices.