The experiences I have had with family present at emergencies have been good, but I STILL think that should not be the default position. We need to get some kind of control over the situation for the health of the patient, and to support the health care team in a very stressful situation. Only then can we support the family- and I don't mean the crowds that show up in OB for a delivery, just those that would normally see the patient naked and ill (ie the spouse or partner, or intimate caregiver).
I also worry about specifically asking the family about coming back to see. They may feel obligated to come, and find it disturbing. We have the spouse/partner in the ER available to answer questions about health history. They either come to the door for more information, or they choose to wait in another room where we've directed the other family members. If they come to the door we (the recorder, or the doc) asks if they would like to come in, and gives explanations or support. We are a tiny ER, sometimes just one RN, secretary, and a doc, so in a code there is NO extra person. The custodian(!) directs family to a private room, and decides if incoming triages need immediate attention, or they can wait til after the code. I'm not kidding.
When life or death situations occur we have to take care of each other. That means limiting stress, including visitors until we've got some control over the situation.
If I was at a huge teaching hospital I might feel differently. If I'm the ONLY nurse, I just can't do it, no matter how important it is. My priority is the patient, the team (if we collapse we can't help anyone else), the other patients with life threatening issues, and then any family of patients. I'm sorry if anyone gets hurt by the way I do things, but we can't spread ourselves that thin and still be effective.