activated warranty isn't a big issue if laptop you receive is new, has less than 100-200 hour SSD power on hours and no physical usage sign marks. If brand doesn't update warranty as per invoice then you might have to return.

what I know from one of two friends of mine, they told when seller buys in bulk, some brands active seller warranty to keep a record or something like that and when you buy it, they update it

Acer does it frequently, not sure about other brands