You ask the question “Is stealthing morally okay?” and you add to this, offering a few specifics. As you’ve invited the thoughts of others, here are my views.
Morality is concerned with the distinction between ‘right’ and ‘wrong’ (e.g. notions of ‘good’ and ‘bad’ behaviour). If one doesn’t recognise the existence of ‘right’ and ‘wrong’ (and considers such principles to be in and of themselves illegitimate) then your question – about whether stealthing is morally okay – becomes redundant. That’s not to say that, from such a position, one still can’t engage with whether stealthing is “okay” – but, if one adopts that position, the issue of ethics no longer plays a part.
As such, your question only has relevancy within the context of ‘morality’. And the difficulty arises that there are a range of moral perspectives – each capable of offering a different response. For instance, if one takes as a point of departure an egotistic and hedonist moral approach, then it’s possible to arrive at the conclusion that whatever one chooses to do out of self-interest in the pursuit of pleasure is “morally okay”. If stealthing achieves the satisfaction of desires, it is – from this standpoint – acceptable.
However, most approaches to ethics tend to recognise and prioritise a sense of ‘the social’ (identifying and responding to the needs and interests of others). For instance, a utilitarianism morality might seek out to maximise the well-being of the majority of persons. In which case, if stealthing is contrary to the majority interest then such activity is not moral.
The point is, there’s no single – or ‘right’ – answer to your question. Rather, there are a multitude of possible perspectives and opinions. As you’ve framed the question in a moral way, my own response is: stealthing is not ethically acceptable (as my view of morality is socially delimited). Considered in terms of my ethical framework, if someone wants protected sex so it’s morally wrong to stealth them – as doing so is directly contrary to their expressed wishes.
One can, of course, address your question in ways other than ‘morality’ – e.g. in terms of law. And, as I’ve noted above, one might debate whether stealthing is okay without invoking morality … such an issue becomes highly complex, as the idea of whether something is “okay” is often framed in a moral sense (and, if we’re to assess the question amorally, this framework would have to be transcended). I’ll leave that for others …