For instance, in unsupervised acquisition of lexical information (such as subcategorisation frames for verbs) from text, the usual methodology is to (partially) analyse the text, retaining only reliable hypotheses which are then filtered based on the amount of evidence for them over the corpus as a whole.
brent (1993) only creates hypotheses on the basis of instances of verb frames that are reliably and unambiguously cued by closed class items (such as pronouns) so there can be no other attachment possibilities.