I can only share my own experience, which is based on the presentation of electronic tickets printed on paper at the entrance. If possible, print on a good printer so that all barcodes are flawless, do not bend or wrinkle the paper in place of the code. Otherwise, you will be long and tedious to read. And the most important advice, banal to the point of impossibility: do not post your ticket photo on social networks. It is easy to steal it in this case. Otherwise, no problem.
There should not be any unless there are additional restrictions. Electronic tickets have long taken root for events, train, plane, exhibitions, etc.