Any drawbacks to the following...?

[chadi]

Are there any drawbacks to allowing addon domains, parked domains, unlimited pop3 and unlimited sub-domains?

Especially for shared hosting?

[pirania1]

Not if you are able to offer it.

[ccccanada]

No Drawbacks as long as you don't expect to get new business from the same client.

If you allow unlimited addon domains the client could theoretically resell his server space to others without you having control over it except by diskspace and bandwidth limit.