Not the place
a few things prevent this.
first, most sale prices do not go in effect until the day of BF. there have been a few circumstances where pricing has been active before, but it is just a fluke. so buying ahead will not get them the good deal, just the normal employee discount.
second, on many of the doorbuster type of items, there is a known quantity, and they are kept track of. and for stores with ticket/voucher systems, it is just that much tighter.
third, store policy. each is different, but Im sure most have something in place to prevent employees from holding goods for themselves. management and AP/LP take particular notice of what employees are buying at this time. stashing of goods is also done, and gets noticed. depending on how friendly the employee is with LP, this could be cause for an internal investigation. you might be surprised at how many internals actually do go on.
the LP info is between first and second hand knowledge. my brother was AP/LP at store and district level for a number of years. I wont say where, but this info is pretty "spot" on.....