Ok, brainstorming here we go
If you bought the 1000 copies and never sold a single one, would you then make any money from sales made by the other authors or the publishing company?
In other word, do you know how many copies should be sold by other people in order for you to be profitable?
Do you know who the other authors are?
Are these authors that you would like to be seen in company with?
Have you any way of verifying how many books have been sold by someone other than you?
For how long will they keep promoting the book?
Do you have any specific information about these book-signings?
Have you contacted the places where the book-signings will take place to verify the information from the company?
Do you trust the publishing company?
Do you personally know and trust someone from the company?
Have this company published previously?
Have they published something similar before?
How did that go? - for the publishing company? - for the co-authors?
Have you seen any of their former work?
Regardless of how this turn out you should still keep working on your own book.