Just verified myself.  

Sender (my laptop) can't clawback the payment because I went out of my way to lock the ecash to the public key of the recipient (my phone). 

My phone (offline) has a "later" button when receiving offline.  

It shows up in my offline phone's transaction history when press the receive "later" button.  But you can see at the time how much the ecash token is worth and the fact that it is locked to your public key (can't be redeemed by anyone else before you can get to WiFi).   

Offline instantaneous receiving of sats that are tied to your public key.  Amazing.  

 https://image.nostr.build/43a115316cd1d767580d2e1a0fe52ad836c1e4220dd8b7e9efe3fbf7650c83d3.jpg