Cashing in chips

When I try to cash in 3k or more in chips at the casino cashier, they ask for my players card and then log my info with the value of chips being redeemed. I have to break up my chips into groups of 2500 or less. Casino cashiers have told me they are not allowed to explain why they do this or what the exact threshold to log the data is. Does anyone know why this is done and how the data is used? Can I refuse to provide my ID and if so, can they refuse to redeem my chips? Any input would be appreciated.