It's very transparent when somebody contrives a reason to do something good because they prioritise based on what gains them the most social favour. Everybody is aware of it and recognises what they're doing, everyone.

But it then allows egoists to discredit people who do good things as 'virtue signalling' because they can't admit there genuinely is a world where opportunities to go good present them selves (which is everywhere all the time) and people act selflessly in response.