I have roofed for 30years and roofed almost all types of roofs,barns,domehouses,commercial and in all that time I have never left a roof open overnight therefore never had no problems. Yes it is brutal work. I'm sure glad that I got out of it it takes a toll on your body as mine is shot!
My roof was not exactly open. I had torn off shakes and had felt and 1x4 strips in place but no lock seam metal on. I did not like it. I have been over booked all year and this is a job I had no time for. I have some large projects clamoring for me to get there and people pushing to be first. I have people who try to pay me in advance and they expect me to be God and turn off the weather. Four more years and I am retiring. That is the only thing that keeps me going. . I'm expecting a huge recession soon so I might be forced out of business before that.