Come on in and rest a spell. Take off your shoes...
After several years of activity, I have never felt the need to lock my Twitter account (s). The only people I have ever blocked were some porn accounts who weren't going to use my "Follow" list to advertise their business and one pervert whose language was of a pedaphilic nature. Over the years, I accept that I have not endeared myself to a few folk and they have blocked me (although they tend to read my tweets one way or another anyway) - all par for the course.
Occasionally, I get tweets I just don't bother answering. These tend to be from anonymous tweeters, parody accounts, folk who are just being facetious or complete nutters. Depending solely on my mood, I sometimes answer them, but reserve the right not to. I haven't blocked them and I have no intentions of locking my account. You could fill my timeline with replies and the decision is solely mine as to whether I press my Reply icon or not. I certainly don't feel obliged to do so. Especially if there is inuendo or allegations without proof.
Locking your account so that 'Only confirmed followers have access...'is effectively preaching only to the converted. You create the comfort of tweeting for the benefit of the Noddy Club - the backscratchers. You can avoid the hard questions which you simply cannot answer. I suppose it saves you time trying to think up those new put downs for your opponents which often replaces honest discussion and debate. In my mind, it could be seen as the coward's way out.
The favoured few who you have deigned to let into your secret assembly have difficulty retweeting your gems. They are lost to the world on possibly its most effective medium of mass communication. Again, only the already converted have the benefit of your wisdom.
Some boys on Twitter e.g. my friend #Hamblin come under a lot of flak for the things they tweet. (Not least, at times, from myself) Whatever their motive in keeping their account open 24/7 (not for me to judge) at least they do so. They don't run scared. (Update: I am now blocked from him too) I accept that some folk perhaps need the privacy. The parapet seems to be a pretty dangerous place to raise your head, although if you can give, then decency demands that you take.
The only time my Twitter account was inaccessible was when I was suspended :o) I still laugh at that one. #TheGreatSkedaddle
So, we are still open for business. Truly, whosoever will may come...