Debounce could make the behaviour of "not always ringing when a guest
enters" feel "buggy". Throttle makes it clearer that it happens to
prevent it from ringing too frequently.
Also move Throttle time from magic number to constant for
a meaningful variable name.
Both debounce or throttle could be used to prevent a spammer from
annoying the moderators.
With debounce, a spammer won't even be noticed by the mods, but
there won't be new notifications for legit guests during the spam.
With throttle, a spammer could still annoy the mods, we would only make
the interval between notifications bigger.
It is a tradeoff. An ideal solution would be preventing spamming from
the same user, but probably unnecessarily complex.
