i noticed that the post office stamps over the barcode of the express satchel with date and suburb of purchase when i buy. is this only because i pay in cash or do they do this for card purchases too?

im just concerned that the stamp puts the parcel under more scrutiny in some way. obviously i am not doing anything illegal by sending cash but im just worried it raises the risk of a postal worker nabbing the money, because of this extra scrutiny.

the PO worker told me the stamp just proves the satchel has been paid for, but i thought maybe they only do this for cash purchases?

i could easily rub that stamp out before sending to help alleviate some risk?

anyone have any intel on this/ experience?

thanks