Android : How can users launch internal activites

I have got 3 identical crash reports on GooglePlay, where the stack trace looks as if the users directly launched an internal activity (which has no intent-filter for category LAUNCHER set in the manifest).

Is there a way to do that, which I missed so far? Can one create a kind of shortcut from the current activity and use it later on to directly launch that activity?

Here is the stack-trace from GooglePlay:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.eb.ohrh.parawind.free/eb.wind.activity.logbook.LogBookSingleDispActivity}: java.lang.NullPointerException at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1728) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1747) at android.app.ActivityThread.access$1500(ActivityThread.java:155) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:993) at android.os.Handler.dispatchMessage(Handler.java:130) at android.os.Looper.loop(SourceFile:351) at android.app.ActivityThread.main(ActivityThread.java:3814) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:538) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:659) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.NullPointerException at eb.wind.views.mapv2.MapWithOverlay.isFlightMode(MapWithOverlay.java:599) at eb.wind.views.mapv2.MapWithOverlay.bindToModel(MapWithOverlay.java:335) at eb.wind.activity.logbook.LogBookSingleDispActivity$MyPagerAdapter.<init>(LogBookSingleDispActivity.java:189) at eb.wind.activity.logbook.LogBookSingleDispActivity.onCreate(LogBookSingleDispActivity.java:39) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1082) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1692) ... 11 more

LogBookSingleDispActivity is an internal Activity. It can not be launched without some preparation steps of other activities.

Any idea, how this can happen.