Sorry this may be late.
My wife's '05 RL had the same problem. The alarm would go off at random times. Even in the middle of the night! My research here and on other sites showed that it might be the alarm connection on the hood latch. It has an alarm switch attached. So, I learned how to disconnect the switch by unplugging it and sealing the connection with electrical tape.
I may replace the whole hood latch assembly but it's been fine since with no alarm blaring at all hours of the day and night.
Good luck and I hope yours is just as simple of a fix.