Detect cracklock for trial application

Question

I'm designing a trial version of a simple C# application. The licensing is build with rhino (https://github.com/ayende/rhino-licensing) and to detect that the trial period is expired the obvious way is to compare the expire date from the license file with current date time and/or use NTP. However NTP is not always avaliable (the program can be started without Internet access) and comparing the date to System.DateTime.Now is not a good solution if the user has started the application from crack lock (http://william.famille-blum.org/software/cracklock/). Is there a reliable way to get the current date (without NTP) or to detect crack lock or other date freeze software?

Thanks in advance.