#No, they should not be allowed#
There are many of us who would strongly object to this. It could create serious problems with underage readers, and could also be seen as indecent, inappropriate, offensive and/or unprofessional. I for one would not want to ever see this material come up in my browser even inadvertently (note that the provided answer appears on a question not even asking for that type of lens), or want those looking at our community to believe we condone this sort of behavior.
Decency may be largely a cultural thing, but it doesn't change the fact that a significant portion of the community would still likely find this makes visiting Ask Ubuntu a very uncomfortable experience, to say the least. The Ask Ubuntu FAQ encourages readers to flag anything they find to be inappropriate, which is what my position asserts it is.
