 For example, "underground" cassettes are, as a rule, not found in mall stores, cassette stalls, or any other conventional retail outlet.It is, in fact, illegal to sell them, as the Indonesian government does not collect any tax on the transaction.As a result, music producers and the musicians they work with have since 2000 begun to open underground boutiques ("toko underground") in Jakarta, Bandung, Surabaya, Denpasar and other locales.