Herman is a smart and excellent poster, but the law he cites is totally inapplicable to Society priests as it pertains to and regulates parish priests, not all priests.
The Society notwithstanding, there are all types of situations where priests don't fall under the authority of the local Bishop. Brotherhoods, the Paulists, Father Wickens etc.
There are people married on boats, just as there are masses given on the battlefield, just as you as a layperson can baptize someone in certain limited situations. I'm not much of a canon lawyer but the more I read the more it seems that the historic church seems more focused on the issue that the sacraments be administered as opposed to how they are administered.
Incidentally the "mass anywhere" concept (which is inherent throughout canon) is how the society is able to perform valid masses.
If any of the society sacraments were not valid you'd hear people in authority screaming bloody murder, but those of good conscience won't and don't. Just as they won't take action against Society worshipers because they know better. They know we're doing no evil and committing no sin, so the best they can say and remain credible and honest is to make claims of "irregularity", "error" etc.
Also, if I may be permitted a very uneducated guess I would venture that many of these kinds of laws - such as the one Herman posted - were addressing issues during times when intra-parish politics were quite intense.
All legitimate priests are either parochial or religious - either they are affiliated with a parish through a diocese, or they are part of a religious order with a prelate superior.
Priests such as Fr. Wickens are not in some different situation. He, for example, is simply under punishment by his Bishop and has chosen to ignore the canonical sanctions imposed on him by his Bishop and continue saying Mass off in his own venue and church.
There are people married on boats
For this to happen, it must be done by your Pastor or with his blessing for another to do so and in such a location. I got married outside my parish and had my children baptized elsewhere. Each time I had to go and visit the rectory and get letters from my Pastor stating that I was a member in good standing of my parish (Holy Trinity in Boston for my wedding, Corpus Christi in New York and St. Cecilia in Philadelphia for the Baptisms) and take those letters to the priest and Church where I wanted to have the sacrament performed, which happened to be in Pittsburgh.
Incidentally the "mass anywhere" concept (which is inherent throughout canon) is how the society is able to perform valid masses.
The problem with Masses is not the issue of validity but of passing off the Mass as something approved by the Catholic Church to occur publicly to which the faithful can legitimately make donations. Mass anywhere refers to private Masses. The Society is correct in calling their churches chapels and shying away from anything smacking of parochialism, since they are not parishes by private chapels set up without permission of the ordinary for mass to occur in them.
If any of the society sacraments were not valid you'd hear people in authority screaming bloody murder
The society goes to great lengths to stretch Canon Law in these situations. See their writings on "common error" and "the state of necessity".
Also, if I may be permitted a very uneducated guess I would venture that many of these kinds of laws - such as the one Herman posted - were addressing issues during times when intra-parish politics were quite intense.
They mostly had to do with regulating a chaotic and uncanonical medieval situation where people and priests shopped their services to avoid canonical discipline or contract clandestine marriages. The laws restated the traiditonal practices dating back to Apsotlic times of doing nothing without the blessing of the Bishop of the place.