I think the first doublequote around "red" is terminating the string in the first part of your ? : expresion. If it were me, I'd verbose that out some:
<% if @tour_request.booked_datetime then %> <p> <span class="label">Confirmed For:</span> <%= @tour_request.booked_datetime %> </p> <% else %> <p> <span class="label">Date and time requested:</span> <%= @tour_request.daterequested %> </p> <% end %>
That way you're not so much mixing the markup & the ruby, which always winds up confusing me.
Also--having .booked_datetime and .booked_datetime_string methods seems odd--consider writing a format_date helper to use to make dates pretty if you need to get fancy.
HTH,
-Roy