It's really a yes & no answer. If I were you, I also hard to make decision.
On the other side, we can say that the maid is quite honest, as she no need to tell you about this ah!
May be you can talk to the employer to get their comment as the bun bun already worked there for 8 years. If necessary, you may visit the employer to see if they welcome you to visit them. I think it is worth to understand more about the maid as yours is 2 yrs old.