It is illegal for a tender company to open bids at the place specified in the unlisted announcement. If a tender company changes the place of bid opening, it shall make a supplementary announcement through the original tender announcement or take the form of an addendum book five days before the deadline for bidding.
As a result, some bidders can't submit their bidding documents in time, and there are cases where the tenderee colludes with the bidders to avoid some bidders.