As you're obviously aware, the related_tweets endpoint was depreciated with the release of your REST V1.1 API.
This has caused many of us headaches when wanting to fetch a conversion of tweets.
I've looked at the HTML markup for your mobile site, for a public tweet (conversation), and it would be very easy to parse the HTML to return a list of tweets and/or tweetIds.
Would you forbid me doing this?
If so, could you please make an exception and allow this, seeing as features we've previously built are now broken.
I realise we could possibly fetch a conversation of tweets using the in_reply_to_tweet field, but this seems like a lot of calls when I could just get the data I need in one request.