The government was definitely threatening him with over 30 years, perhaps not privately, but it is not a falsehood.

"If convicted on these charges, SWARTZ faces up to 35 years in prison, to be followed by three years of supervised release, restitution, forfeiture and a fine of up to $1 million." (http://www.justice.gov/usao/ma/news/2011/July/SwartzAaronPR....)

Not pleading out would mean that the offer of a lower sentence is off the table, and the prosecutor would push for the threatened maximum sentence.