emma,
for me, i also do not leave my dd alone with my maid at home. at most, maybe for no more than 30mins, if i have to go down to the shops quickly to pick up some things and it's not convenient to bring my dd (eg. when she was sick). if not, i will always bring my dd with me.
for me personally, i do not like the idea of leaving kids alone at home being taken care of by the maid, esp. if the child is still very young, ie. babies or toddlers. that's because the child is young and not able to tell you exactly what happens or what the maid does.
and young kids are not easy to take care of the whole day, so can understand if the maid gets frustrated or can't manage. when this happens, very likely the maid may take it out on the kids. also, you aren't able to monitor the maid, esp. when you want things done a certain way.
i feel kids who are older, ie. at least 6-7yrs old, are more suited to be left home alone being taken care of by maids. because at this age they are much older and less likely to be easily "bullied" by maid, so maid can't anyhow do things at home without the kids telling on the maid. also, older kids are much easier to take care of, so the maid will be less stressed and less likelihood of maid not doing her job well.
having said all this, i feel a good and reliable maid, esp when it concerns childcare, is VERY rare & hard to find. alot of working moms i know who have no choice but to leave their young kids alone at home, always tell me no choice, they gotta close one eye lor. but for me personally, i can't accept "closing one eye" when it comes to my dd leh. when it comes to her welfare, safety and well-being, i expect nothing but near-perfection, so that's why i don't trust anyone else to take care of her.
even now at home when my maid helps me with my dd, sometimes she does certain things that i don't like, and i never hesitate to tell her off. she probably thinks that i am soooo fussy when it comes to my dd, but i have made it clear to her that when it comes to my dd, YES i am VERY fussy, and she MUST do things my way and according to my standards, and i do not accept compromises nor do i make any apologies for it.
i am ok with closing one eye when it comes to household chores, etc. even when my maid makes mistakes with household chores (eg ruin my clothes when she ironed or washed them) i have never scolded her, and even told her no need to pay me back (even when she offered) cause these are just material things and i know she made mistake and didn't do them on purpose.
i guess my advice to you is to do whatever you are comfortable with. but it's not easy having a maid lah. they do need to be constantly monitored and supervised. sometimes it does feel like there's another person you need to take care of.
my maid is very capable and has a very good attitude, and even with such excellent attributes she still needs to be monitored time and again. so can you imagine what it's like if the maid is extremely incapable, untrustworthy and has a bad attitude?
anyway, i will be maid-free soon, most likely by the end of the year, cause my maid's contract ending soon and next yr onwards i won't need a live-in maid anymore once dd goes to sch.