this issue of claiming a dependent or not gets misunderstood.
As the taxpayer, you always have the option to claim or not claim your dependent. The IRS does not care.
HOWEVER,
your dependent (your daughter in this case) has to answer the question on HER tax return, CAN someone claim her? that answer is always the same, regardless of the decision the taxpayer makes
So for her, she will need to answer "YES, someone CAN claim me", even if her parent's don't claim her
Dependents are not eligible to receive the stimulus directly if they CAN be claimed by someone else.
So, as the parent, you always have the option not to claim her, but her answer is ALWAYS , YES, someone CAN claim be; she is not eligible for the stimulus (and you could lose the $1400 for the 3rd stimulus) because someone CAN claim her.
The IRS was too smart for this potential loophole!
