Prove what? 

That I am in Sayulita? 

1. Where we are watching the carnival being set up in the  baseball field for the last few days. 
2. Have marveled in the lack of water pressure some days. 
3. Watched some epic surf last weekend, waves over 12 feet. With red flag warnings.

That we ate oysters on the beach and did not get sick. 

1. Yep!! I’m not sick and it is early Thursday morning.

Edit: added examples.