Twitter to allow Direct-Messaging anyone

I never understood why they couldn't make this feature work correctly. The most common use case problem I had was I would message a company/brand on Twitter about an issue and they would invariably reply "DM us with details of your order and we'll look into it".

The problem was most brands weren't following me so I could not DM them via Twitter.

Here's a solution that might work better:

1) If a user/account has ever tweeted back at you in response then a DM is allowed.

That would prevent a vast majority of potential spammers from flooding your DM inbox and if they try to spam you publicly, you can mark as spam and get their account banned.

This needs to be an opt-in feature. It's great for companies that need to have an open line of private communication with their customers, but for individuals it opens the doors for other avenues of harassment and abuse, something already running rampant on Twitter and which they have done next to nothing to address.

Is this the beginning of the end of the bubble?