it can't be used, and it's not safe.

1. Compatibility: If the copied cashier system is incompatible with the existing hardware or other software, it may cause the system to fail to work normally, thus affecting the business.

2. Security issues: Copying someone else's cashier system may have security risks, because you don't know whether there are back doors or other security loopholes in the source code, which may lead to data leakage or other security issues.