The smart ones are cocky, just like the black-and-white amahs of days gone
by. Filipino maid Donna, having worked for 3 employers over a period of 8
years has a record she can justly be proud of. She has been highly regarded
by a local as well as by 2 expatriates. She has to some extent bridged the
culture gap, to be able to cater to both eastern and western employers. You
yourself acknowledged that her cooking was superb.
She might have been a good worker, perhaps on par with the black-and-whites, but I have never heard of a black-and-white doing something so dumb and so irresponsible, like leaving the door unlocked! A Filipino maid is generally more confident that an Indonesian maid, for example.
You are right to be concerned. One mistake, no matter how dumb, can be overlooked, but since Donna would not acknowledge her mistake, you cannot be sure that she will not do it again. Her arrogance is an undesirable trait in a live-in domestic worker. But was she arrogant? Only you could tell by her demeanour at the time she left you.
In human relationship, nothing is all black or all white. Do you think that Donna was too proud to acknowledge she was wrong? Or did she have some reason to want out? It appears that she has a point if she should ask to read something before she signs. If she was not totally happy, you might have given her the excuse to leave you. Perhaps you have not been communicating with each other.
You were perhaps a little impatient when gave her a choice - sign up or get out. Did she refuse to sign or was this incident merely an excuse for her to leave your employ? Since you gave her the choice between signing and leaving, you had to let her go. Now with the wisdom of hind sight, I would do it differently. I would count up to 10 and meanwhile ask myself if this is the kind of maid I want to entrust my daughter and the security of my home to for the next 2 years!
If I am convinced that she will not change her ways then I would let her go. But on the other hand, if I am slightly regretful that perhaps things were not so bad after all and that a little bit of pep talk would settle the matter amicably, then in future I would not be so impatient. I would probably get my agent involved, as an intermediary. Sometimes a maid can accept a negative comment from the agent more readily than from her employer because the agent is neutral on such an occasion.