[Kaderin Triste]

First off, you should NEVER feel guilty about doing things (like having your friend find out what can be done) that help you feel secure and safe in an environment that has the potential to be uncomfortable at the least.

I would assume, depending on the location and size of the concert that there probably will be security people, or something of that nature, that can help with any issues with the ex's if they try anything.

Hope everything works out and you have a good time!