Yeah this all happen when the host cell has been exposed to environmental stress. Including UV light and starvation. In either of these cases internal levels of the repressor drop and you get activation. All of these promoters are leaky anyway, what is important is the volume and redundancy of promoter sites. In this case only when the cell has been starving for a couple hours, and finds itself in a condition of excess waste it's not going to be able to keep up the level of protein production to keep the virus from escaping. Same for UV light, even if the cell is growing fine, if it finds itself replicating mutations the promoter and repressor sites are going to change and the repressor won't fit as well, and again the virus pops out.
I would suggest if you want to find a good article either look for a paper where they describe the structure of the repressor (Cell circa 2001) or, look back to the initial sequencing of the promoter region.