I second that. Why? That's a disaster waiting to happen.

Hypothetical situation: Say you have selected a mix of files and directories that you wanted deleted but you happened to select a file that should not be deleted... If the size of this selection is greater than or equal to your size limit, those items will deleted and gone forever.

This happens all the time. Working too fast, not being careful, etc.

This is just 1 of many situations that make deleting trash automatically based on size a very bad idea.

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Rick alias cougar

many people I've done support, or training for empty the trash without thinking as it is, losing data sometimes.

for some users, this might actually reduce the risk to some extent.
and if you limit it to 5-10% of the total HD space, on most drives sold in the last 3 years, this is still at least 4+ GB in most cases.

I'll stick to my own method which is manual, emptying the trash once every few days unless I need the space back immediately. Gives me a couple of days to realize if I actually needed something or not.
But I'm keeping this on file, especially for recent windows converts.