Agreed, one exhibition is allowed. See below from D3 handbook.
17.12.2 Preseason Practice A member institution shall not commence practice sessions in ice hockey be- fore the third Monday in October. (Revised: 1/10/91 effective 8/1/91 and 8/1/92, 1/10/95 effective 8/1/95, 9/2/08, 1/17/09 effective 8/1/09, 1/18/14 effective 8/1/14)
17.12.3 First Contest. A member institution shall not play its first contest (game, exhibition or scrimmage) against outside competition in ice hockey before the second Friday following the first permissible practice date, except as provided under Bylaw 17.12.3.2. (Revised: 1/10/95 effective 8/1/95, 1/17/09 effective 8/1/09, 4/17/12 ef- fective 8/1/12, 1/19/13 effective 8/1/13, 1/18/14 effective 8/1/14)
17.12.3.1 Five-Day Acclimatization Period. Each student-athlete (both first-time participants and con- tinuing student-athletes) shall participate in five on-ice practices, conducted on separate dates, prior to participa- tion in any outside competition including a regular contest, scrimmage, exhibition game or joint practice. An on-ice practice conducted on the same date as a regular contest, preseason scrimmage, exhibition game or joint practice is not countable toward the five-day acclimatization period. (Adopted: 1/18/14 effective 8/1/14)
17.12.3.2 Preseason Scrimmage or Exhibition. A member institution may conduct one scrimmage, ex- hibition game or joint practice before the first permissible contest date provided the student-athletes participat- ing have completed the five-day acclimatization period (see Bylaw 17.12.3.1). (Adopted: 1/18/14 effective 8/1/14)
