In all the versions of nopCommerce, when a customer registers on the website, the customer could be from any country/state, and he/she won't know that in his/her account he/she has to select time zone according to his/her location.
The problem is that each and every activity of that user on the website is according to the time zone saved against his/her account. And, if the user doesn't change the time zone, his orders, website comments, etc everything remains in-correct according to his/her location.
Right now by default every customer gets time zone : (GMT: -12:00) International Date Line West
Time Zone field should be added in the registration form, so that when customer is filling the registration form, he/she will select his/her time zone. By this store owner could avoid any kind of mis-understating with the customer regarding order time / shipping time / request time etc.
In addition, this should be made configurable from the admin section.
IMPORTANT: As, many countries follows Day-Light Saving like U.S, this should also be taken into consideration so that day light saving time change should not create problem and website time zone should set itself automatically according to the location.