On Call 24/7?

I had my third interview and I felt all right about it. Now, the interviews are really to see if the office culture, staff, and myself mix. One common theme that has arisen in all interviews is how hard everyone works. Today, I was told that they all have blackberries and are on call 24/7. If they get an email, they are expected to respond, regardless of the time.

Could this all really be true? The pr firm that I previously worked at was very fast-paced and there were nights when I worked all weekend or was up until midnight finishing up a project. This occurred sometimes, not 24/7. Additionally, I like to give each project 100+%, so I definitely consider myself a hard worker. I'll figure things out soon enough. Another company has offered me a position, so I'll speak with them tomorrow to get the details. Stay tuned.