I'm not the type that brag but the BM respond should be enough to make you understand that there's possibility limited purchase also on exchange site since the project team cant sell or mint Gold token more than the gold saved in secure vault and to maintain or save the token price from manipulation there most be some kind of restrictions to achieve that.
I didn't mention it because it's obvious, ofc you can't buy more than total supply (be it gold token or other crypto).
What I meant was, one user's buy and sells on exchange/marketplace affect the other users actions. If one buys 100 gm gold with ether then the other user will have less gold tokens to buy.
Gold token correlates the amount of stored in vault, that should be enough to avoid price manipulation and if someone sells at less than gold's spot price, it's their choice and none of team's or anyone's business.