I'm a nanny and I wish I can post review of the families I worked on Care.com

Yes, I would - but I would be very clear to just include clear facts, not judgments. So I wouldn't say "all around unreliable" but I would say "was late to work or unable to work a complete day for 12 of the 20 days she was employed with us."

Or "quit the position without notice"

Etc...

But be prepared for a rebuttal if there is another side to the story.

You sound like the kind of MB nannies are warned about. She quit, you're salty, and now you want to exact revenge. If she was so terrible, you would have fired her. She quit. Perhaps it was you or your kid who were terrible.

Maybe you were the reason she quit..

Deleting the profile and posting a new profile is breaking care's TOS, and they will delete the second profile.

I don't have an issue with an employer posting a review of facts. I have a major issue with care allowing people who never employ someone to post anything they want.

Truly unbelievable...I canceled once and it didn't take. I canceled again and they stated they had no record of my original cancellation. So I canceled twice. Now, I just received my credit card statement and lo and behold, they have charged me yet again. What a nightmare! This is a truly heartless organization. Incredibly unethical.

We hired a babysitter from care.com who turned out to be a complete disaster. She repeatedly showed up late. Asked for an advance then didn't complete her hours. Filed for unemployment even though we were clear from the beginning that we would only need her for 60 hours over 2 weeks. Finally, when she found out that we were using another babysitter she sent us a threatening letter. I was genuinely afraid that if we posted a negative review that she would somehow retaliate.

Absolutely would have done this with the one nanny we hired who behaved this way...but she basically left the nannying field and was quitting to do something else. In the end, there was nothing I could do as I knew she'd never list us as a reference for another job.

The lesson I learned was to hire someone who had worked as a NANNY--day in, day out, month after month--rather than someone who had great babysitting references, which the case with the person I had hired.

I wouldn't leave a bad review to be vindictive, but just like PPs said, to let the next family know what honestly happened.

Yes. I certainly wish past employers of one woman we hired had posted honest feedback. Would have saved us some trouble.

I have posted negative reviews, but only with factual information and not subjective (for example: I have posted that nanny failed to show up for first day as agreed, or that nanny agreed to start date and then walked out mid-first day after receiving a phone call; but I did not post that nanny was a liar or flake).

Facts are totally fair.

Yep.

No, she can just delete and make a new profile...

Yes. A factual, honest review that informs another about the individual's job performance is what those should be used for IMO. (I hate bad reviews when people were never hired in the first place, but a review based on actual job performance? Absolutely.)

I would absolutely post an honesty review of the sister's service. If she was great with the children I would include that while also relating that she was unreliable.

What was the reason she gave?

If you hired someone who quit on you abruptly after less than a month on the job? Was unreliable/unprofessional and all around a disaster and a flake? I'd hate for another family to make the same mistake we made, but maybe I should just let sleeping dogs lie?