Honestly whatever your feelings this is a bit embarrassing. This was obviously done in a way and at a place to provoke people and she clearly knows that too.
Well, no. She spent all day in a room filled with lesbian, gay, bisexual and straight ppeople, some of whom were trans, all wearing the t-shirt. Then had a great time at the after party, everyone getting a little tipsy and a lot happy. When that finished at 11pm, they decided to go to a gay club to keep having fun together - there were people there from down South as well who don't come to Scotland all that often (or ever).
It's much more likely she didn't give her t-shirt a second's thought (which is why she didn't even understand why they took her aside at first). And to be honest, whatever your politics, if the same club wouldn't kick you out for wearing a trans org t-shirt excluding the LGB, they also shouldn't be kicking anyone out for wearing an LGB one excluding the T. Both are legitimate groups with distinct and sometimes mutually exclusive goals.
Having distinct and mutually exclusive goals is typical for different protected groups. And the Eqality Act is the mechanism by which we resolve the conflicts arising from and between these groups.