First Amendment/Universities question

[Lynda Dodd]

I teach political science & constitutional law classes at Miami University of Ohio (a public university).  The maintenance workers are currently on strike, and many faculty and students are wearing armbands and buttons to support them.  I'm pasting below a news account, describing the university's attempts to require all those attending a football game last weekend to remove any armbands or buttons.  Although the university does check i.d.'s at the entrance to the stadium, students do not pay for tickets.  Wouldn't the stadium event count as a public forum?  I'm not as familiar with this area of First Amendment law as I should be, and I doubt I'll quickly find a fact-pattern that is on point.  It seems to me that the university here is way out of line.  I'd appreciate any help with this question, as I know many students will be asking questions about this all week.

[snip]One of my students sent me an email today and told me that during the
football game on Saturday she and several others were not permitted in the
game with their green armbands on, with their pro-union shirts, and one was
forced to remove a button promoting Howard Dean.  She said that she asked
the administration to put it in writing, and they would not do it, so they
filmed this.

Here is a link that appeared in the Middletown paper.  Note the comment by
Richard Little who said that the "university does not allow group promotions
into the stadium."  Then noone with greek representation?  Noone with the
university logo?

http://www.middletownjournal.com/news/newsfd/auto/feed/news/2003/09/28/1064724029.19830.3624.2651.html;COXnetJSessionID=14sGXkRiIY8DFsjo663LxPyhgURhxfKb7Ccq0i02h4lU1x1d0H8V!-284502201?urac=n&urvf=10648894784320.8970818082985101

CK
[snip]