What is the anonymity set for a participant?

[dbosk]

the paper also postulates a sybil-proof anonymous credential
system. While the proposed approach achieves non-linkability across
different crowd event, the anonymity set for any participant who
contributes to the count is limited to the set of all those who have
obtained these credentials. In other words, in order to achieve meaningful
privacy for the proposed use case, these credentials need to not just
widely available, but also widely issued. That seems like a huge step
to simply assume.

Emphasize the wide deployment of BankID in Sweden further.