And the same regular expression evaluator
that they use to look for the email address can by used to look for the same pattern you propose - so no, it's not the best way, and for a good spam spider, it's not even a good way, and to the spider, there's no difference.
To match a regular email address like email@example.com
To match an email address like you showed: me at mail dot com:
and it spits out all the matches.