[tor-relays] Public Tor Socks port

[yl]

Hello,
I wonder what is the reason not to offer the socks port publicly to
users as an entrance point to the tor network?

Assume you run a tor exit or relay on a public server and you enable the
socks port and listen on 0.0.0.0 or so and accept all incomming
connections. Then you post the socks port publicly. What are the reasons
not to do so?

Thanks
yl