tasmaniansyrup wrote

Bring a shoulder bag--like a tote, professional-looking work bag or something larger than a purse that one could slip books into while browsing without looking like they're trying to do anything shady. Try not to be seen in person or on camera doing this, but if someone does see you it's just look like you are stashing your shopping for ease of carrying. Take the bag into the bathroom and check the books you want for rfid tags. If someone is actually enforcing the "no merchandise in the bathroom" rule, this probably isn't the best bookstore to steal from anyway.

If you're worried it will look obvious that you picked out books & then left without buying anything, you could also bring some textbooks/notebooks in with you and spend some time in the bookstore cafe reading or doing work. This gives time for anyone who's watching the shoppers for sus activity to lose interest in you. But use your intuition on what approach is safest.