OK, maybe this is unnecessarily trodding somewhere I don't need to go, but I'm not into the trend of pressuring people to sign reviews.
This turned into a
... https://twitter.com/MiriForbes/status/1288782831628374018
This turned into a

1) I think it requires a great deal of privilege (high stature in field, often white & male) to insulate you from the hard feelings & potential professional retaliation (even in subtle ways) from giving honest critical feedback/ rejection recommendations for someone's hard work
Even though I have tenure now, I don't feel like I have the capital to sign reviews yet. Maybe someday I'll get there, maybe not. But I feel as a woman I have to be more careful about it.
2) It's problematic that authors would learn so easily who their easiest and harshest reviewers are, when most journals allow authors to suggest their own reviewers (and many rely on these recommendations)
3) I just don't understand the goal. "Transparency" is a tenet of open science, yes. But it's a means to an ends, not a goal in itself. Transparent science allows others to check our work and hold us accountable. What problem does transparent reviews solve?
One could say that it helps us be nicer. We could just BE NICER without pressuring reviewers to potentially jeopardize their careers.
Plus, for all the complaints about Mean Reviewers 2, there are also crackpot studies (Bem!) that slip past peer review & strain credibility of the field. We NEED Reviewers 2! We NEED to be ready to reject papers that come from their respected colleagues. Sometimes papers are bad!
Transparency isn't a universal goal in all aspects of science. It's not something we implement in, say, double-blind clinical trials. We keep them blinded for a reason because the blindness serves a purpose.
4) This is all especially compounded by the fact that fewer journals are blinding the authors. That's a whole 'nother can of worms. You can't tell me you're not biased at least a little when you read a study by a superstar author (or by a friend/ colleague).
So that's my beef. Sign reviews if you want. But I don't like the trend of people feeling pressure to do so. Instead, write your reviews with compassion and constructiveness, as if the author was your student or a dear friend. But, duh, that's just called being a human being.