Our local does this www.commongrounds.co.uk/
Prior to having suspended coffee it had a board up that you could buy coffee etc for friends to enjoy later.
I don't know if they have 'criteria' for suspended coffee but as they have huge links with the local community and NGO's I imagine many of them would already be familiar with some of the local folk finding things tough.
They also have a Christmas dinner (on the day itself) and it is open to homeless, living alone, elderly, sp, immigrants, foreign students etc - basically anyone who might have been spending Christmas alone or with very little.
I am an atheist and detest many aspects of organised religion however the act of taking care of your fellow man and woman is a wonderful thing.
For anyone rightly pointing out the cost of coffee etc, yes that may be a concern, however recall the thread about biscuits at food banks? Sometimes having a 'treat' that you would never have otherwise is a tiny but significant boost.
Like when you buy a friend a present of something seemingly frivolous because a) you know they will enjoy it and b) it's not something they would likely buy themselves due to the cost or needing to spend the money on something more important.