Turbo Tax is a self prepared return. It has no way of knowing or checking that you entered something wrong or in the wrong place or entered something twice Or left something out. It doesn't check against any outside sources. The IRS has copies of all the W2s and 1099s your employer and banks/brokers, etc. sent in to match against. Turbo Tax only checks the calculations of what you entered. It is your responsibility to check it over before you file. They only Guarantee that the calculations are right based on the entries you made.
https://ttlc.intuit.com/community/charges-and-fees/help/what-is-the-turbotax-100-accurate-calculatio...
In the Online End Users License Agreement I found...
scroll way down to 2. Services (see last sentence)
2.4 Import Services. The Services may include a feature that allows you to import, where applicable, certain information from participating financial institutions (including those offering a TurboTax for Online Banking interface), payroll processors, personal financial software, business financial software such as QuickBooks and charitable deduction information from ItsDeductible branded service. You are responsible for verifying the accuracy of the information that is imported.
From https://turbotax.intuit.com/corp/license/online/
