This can be accomplished with a third party plug-in, the Locale Button Plug-in.

You could add a the same button condition to every situation. Normally, the button is ON which means that the Button condition acts like a noop. But if you toggle the button widget OFF, it would prevent all situations using that condition from ever activating.

Good news!

Android 4.0 finally grants apps official access the built-in calendar, so we’re planning to support this with a new Calendar condition. This new Calendar condition will be Android 4.0+ only.

As a general design principle, Locale only has features that Android officially supports (for the developers out there, we only use public APIs). This ensures that Locale works reliably across different versions of Android and different Android devices. For those without Android 4.0 (or those looking to live on the edge), there are some third-party plug-ins that implement Calendar condition functionality. These plug-ins are using undocumented Android APIs, and may therefore not work on all devices or may break when new versions of Android are released. Anyway, here are links to these plug-ins on the Android Market:

https://market.android.com/details?id=org.acm.steidinger.calendar.localePlugin

https://market.android.com/details?id=com.DroidMunkey.LocaleCalendarConditions

The free Day & Night Locale Plug-in is now available on the Android Market. This plug-in implements the original request of detecting sunrise/sunset based on time of year and latitude.

https://market.android.com/details?id=se.akerfeldt.locale.sun

Wi-Fi location training is now available as a feature in Locale 1.2. It can be found under the Menu of the Location condition.

We strongly discourage the use of third party location conditions or Wi-Fi conditions. These are less accurate and require more battery power. Instead, users should use the built-in Location condition and use Wi-Fi training if necessary.