California Realtor here. Escrow is opened by the listing agent and 99% of the time the seller/listing agent chooses the escrow company. Escrow is opened once there's a contract.
The cancellation provisions are found in Paragraphs 14C (1) and (2), and in Paragraph 14E of the CA-RPA. Regardless of the reason, the seller must give some type of notice to the buyer, however (either a Notice to Perform or a Demand to Close Escrow) before the seller can cancel.
Escrow is generally considered good because it protects the buyer and seller in a transaction.