As discussed previously, in some situations Texas courts will afford customer lists trade secret protection. In most non-solicit/non-compete cases, the departing employee doesn’t walk out with the company customer list. In some cases that list doesn’t exist. In other cases the former employee will simply reconstruct the customer list from memory, contact information they maintain, or even the phone book – the "phone book defense".
Texas courts have held that "A customer list of readily ascertainable names and addresses will not be protected as a trade secret." So if a departing employee sells construction equipment there is a limited number of potential customers like contractors and sub-contractors. Those trades advertise in the phone book on the internet and in trade publications. As a result the customer list can be reconstructed quite easily and will little effort.
In most circumstances the employer simply can’t rely on protecting their business by identifying their customer lists as a trade secret. They will also need a robust and enforceable non-compete and non-solicit.