LFS Quarantine?

Do fish stores ever quarantine new fish as a rule or would that be
expecting too much - i.e., loss of profit from holding back stock...
It would be great to know that when I went to my LFS, the fish I chose
had already been quarantined and deemed healthy. I know some stores
will give you credit or refunds if the fish dies within a number of
days but does anyone guarantee healthy fish? Just curious.