The authorities are clamping down on overstayers. It is under the law that tourist should carry their passport or copy with them everywhere they go. If they fail to produce such identification during a check, they can be fined up to THB 2,000. However on normal circumstances, you will be hauled to police station and only be released till someone brings your passport to the station for verification.
Long term residents, Thai driving license will not be acceptable if the check is specifically for your visa validity.
Anyone travelling out of the province where you reside for more than 24 hours is to bring along your original passport with you as well.
