One of the Canonical norms most roundly ignored by the diocesan clergy and hierarchy worldwide is the norm for a priest to ordinarily offer only one Mass a day, even on Sunday and Holy Days. A second Mass and even a maximum third Mass (on a Sunday or Holy Day of Obligation) is exceptional and permitted only in certain (and presumably unforeseen) circumstances due to a shortage of priests. In many parishes there are too many Masses on the schedule given the number of priests available and the problem would be easily solved by revising the schedule to include less Masses, to correspond more accurately with the number of priests available on a given day.
The point of the law is that, although a second Mass may be permitted under certain circumstances, no one has the authority (neither pastor nor the bishop) to obligate a subordinate priest to binate, ever! The present practice of scheduling and expecting priests to say more than one Mass a day on a regular basis is an blatant abuse of authority.
Here is the relevant canon.
Can. 905--Par. 1. Apart from those cases in which the law allows him to celebrate or concelebrate the Eucharist a number of times on the same day [viz. All Souls and Christmas], a priest may not celebrate more than once a day.
Par. 2. If there is a scarcity of priests, the local Ordinary may allow priests, for a good reason, to celebrate twice on one day or even, if pastoral need requires it, three times on Sundays or holydays of obligation.