I have slightly mixed feelings about this. I don’t know the full story of the content warnings for this version of R&J, but as a general principle I think they are over-used and pander to what can seem like a desire for everyone to be ‘protected’ against everything.
The theatre is supposed to stretch us - it was founded on notions of catharsis, so audiences could live through the adventures of the characters and ‘purge themselves’ of often difficult or violent emotions. If we sanitise everything this aspect of it all will be lost.
On the other hand, if someone is particularly sensitive to a particular 'thing', it makes sense for them to avoid it. I've always thought, for instance, that rather than age-related certificates on films there should be warnings to parents who can then decide on the suitability for their own children (and this applies to adults too), so that people can screen out things they don't want to see - even if it's a temporary measure whilst they are still grieving, or until they feel able to cope with whatever the situation is.
On the third hand ?, there are so many possible 'triggers' that it's reaching the point where you can't hear a poem read, or watch any form of entertainment without having to hear about the content in advance - it can spoil the experience before it starts.
I do like the poster, though - I'm tempted to send for a tea-towel.