Agree with petpeeve! And I'll add in that this is very, very common. Many dogs try to experiment with how much they actually have to do to get that treat at some point, and I've known a lot who go through phases of pretending to pee.
If you suspect she really does have to pee - for example, if she's been napping for a couple hours and this is her first trip out - and she only fakes it, you can try bringing her back in for a couple minutes, putting her in a crate (if crate trained), pen, or just have her tethered to you so you can watch her super closely, and try again in 3-5 minutes. Basically, she doesn't get freedom until you're positive she's actually emptied herself, so she can't go off and potty on a rug while you're not looking.
If you suspect she really does have to pee - for example, if she's been napping for a couple hours and this is her first trip out - and she only fakes it, you can try bringing her back in for a couple minutes, putting her in a crate (if crate trained), pen, or just have her tethered to you so you can watch her super closely, and try again in 3-5 minutes. Basically, she doesn't get freedom until you're positive she's actually emptied herself, so she can't go off and potty on a rug while you're not looking.