The devil's in the detail. It says "from 6 July to 23.59 on 9 July"
So, the sneaky devils actually mean: "from 11.59 6 July ..." I bet.
That would be very odd; if that is the case then it could also be from 23:59:59 on 6 July.
I would have thought that they actually want people to use it rather than trick them; I suspect that some people will have given up already and won't try again all weekend.
It is very annoying; maybe they do it to avoid having to work out all the various world time-zones, especially as they are based in the US who have many time zones... so they decided at an early stage to not say the start time, for fear of the backlash as people in different locations moaned 
Possibly. Maybe they could accept that large numbers of the world's population aren't stupid and understand time zones and could therefore work out the start time in their county if they specified the time zone in the start time.
well they give a definite end time, so which timezone is that in? As its a UK site I assume its UK timezone, but if the idea is to get people to resubscribe, then maybe the email should have either given a start time or have been sent once the free period began. As stated, some will pop on, see its not free and simply left again.