I have a small script, that functions as a broadcast receiver, and which I have programmed in Python (the script hands off processing to another main Python program). I don't know Java. In order for the receiver to function, however, SL4A naturally needs to keep running. As far as I can see:
Given this, are any problems likely? I should note that the phone in question is not going to be used much for calls etc.
I ran an application with more than 3 threads for hours in daily use without a problem. But I used the method to turn the script into a standalone APK. This method can be found in the SL4A FAQ.