For such income, the tax authorities will not know in advance, because the relevant income information will not be directly transmitted to the tax authorities.
However, the related income is realized through online transactions, and the related transfer and remittance records are relatively complete. The tax authorities can obtain relevant information, find out relevant income and expenditure, and determine which income belongs to taxable income.
Therefore, once the tax bureau knows that there is a problem of underpayment, the tax authorities can easily verify it, recover the underpayment, add a late fee, and impose a fine of more than 50% and less than 5 times the amount of tax evasion.