The law does not forbid the printing of ID numbers on membership cards, given the consent of the bearer and the fact that the card issuing entity has informed the bearer of the purposes of having their ID numbers printed on their membership cards. However, the PDPB recommends that, unless necessary, institutions avoid this practice, and use the membership or customer numbers instead, to reduce the personal data to be processed. While the PDPB has no guidelines on how many digits of the ID numbers may appear on a membership card, it is advisable to omit 2 digits of the numbers.