Yes, Apple will let you return your P4 for up to 14 days. I just checked my order. Clicked "return", and it brought up the box telling me I had until April 5th to return it. Never had issues with Apple taking returns in the past. I am sure their reseller agreement with DJI allows Apple to take back the P4, and either resell it as used. Or return to DJI.
Normally I purchase almost everything from Amazon. 30 days, no questions asked on just about anything. Of course I spends thousands of dollars with Amazon a year. But they have let me return dozens of high end devices, electronics, musical instruments, etc. No problems. And it is so easy. Pull up your order, and click return. If you select defective item, amazon prints you a free return label. If you just want to return for any reason, they just deduct return shipping. Something like a P3/P4 they would probably charge you about $10 dollars for a return. Pretty good policy IMO.