Generally, audits are done at random, so your presence there doesn't influence the IRS.
They typically call an audit for people with more complicated tax returns. (Someone who files a cut-and-dried 1040EZ doesn't usually get summoned) So, your friend needs to bring whatever records will validify the information she entered on her return for the year in question. You should familiarize yourselves with the records, so if the agent says something like "You've claimed charitible donations of $2,000..." you will know what proof to pull out of the paperwork.
Don't sweat it. It's a pain in the butt, but it's not as bad as you may think...unless she cheated on her taxes.
