Changing an attribute from non-mandatory to Mandatory

We are using eB 15.5.1 and oracle 11. dB

We have a document class in our development and test systems that has not been moved to our production system yet.  It has several attributes that were originally created as non-mandatory and the business user would like for them to be mandatory.  I would think it would cause any issues to check the box to make these mandatory but I wanted to double check first.  Thanks for the help.