If a child support petition is received and you have 30 days to respond, what happens when the non custodial parent does not?

They will enter a default order using whatever information they have. This order tends to be much higher then what would be ordered if the other party shows.

File for a default.

In Michigan Child Support is determined based upon Child Support Guidelines provided by the Friend of the Court. Regardless of whether or not the other party shows up, the Court will attempt to ascertain the income of the parties, the child care expenses, insurance premiums, etc. If a party does not cooperate at all the Court may "impute" of infer what income should be. The Friend of the Court will then make a child support recommendation which will typically become the Child Support Order of the Court. Regardless of whether or not the other party appears at the hearing if you initiated the petition for modification or establishment of support, you should appear in Court.

The Petitioner can take a default and establish an order without the input of the paying party.

This isn't a matter of custodial or non custodial parent as either parent can file the petition. If a person does not respond within the requisite response period, the petitioner can get a default order. The only problem is, the petitioner here likely does not have the respondent's income info so has no basis to calculate child support. Discovery of income records from respondent's employer (if there is one) can solve that problem, after which a default order can be requested.

We will seek a default against him/her.

An order may be signed granting the Petition.