Even today bawdry only generally exists in specialist volumes/sites. In fact Mudcat is one of the few places where bawdry mixes in with other material, but even then most OPs initially put up some sort of warning or disclaimer. Bawdry is material intended to titivate and/or amuse, and whilst it is unquestionably folk material, it tends to have a marked genre with boundaries. The sexual material included in Child does not come under the heading of bawdry and I believe Child did not deliberately exclude any of it. It was not really part of the collections/manuscripts he was investigating. Even 'Secret Songs' has very little if any bawdry in it. 'Rape, incest and seduction' are dealt with in a very matter-of-fact way in the ballads, (but in my opinion where it does verge on any bawdry it is due to the redaction of some editors). Rape, incest and seduction were responded to in very different ways to today, in past centuries. If you were a rich and powerful male they were seen as perks.