What is the lesser evil, degassing too early or too late? Suppose that I have made bread dough and it is supposed to be degassed around 90 min after kneading (t+90). Suppose that I have to leave home at t+30 and will be back sometime between t+120 and t+150. 

What is better for the dough, to degas it too early or to degas it too late? I know I can try to influence the duration of the first rising by changing the temperature (I could either put it in the fridge or in an oven preheated to 50°C, turned off and cracked open). But I doubt that the dough's internal temperature will change substantially during these short times. 

So, what is the better strategy? Warm it and degas early, or cool it and degas late? 

For the record, I am talking about a high-hydration bread (86%), with sugar, but no fat, 2.8% yeast. But if the hydration, leanness and yeast amount have an influence on the decision, I would like to hear about that too. (Assume that for any yeast amount, the time period before degassing has been calculated to be correct for it).
In my experience (and I'm only an amateur baker), you could leave this until you get back and knock it back then.  If you leave it really long (e.g. 24 hours), you might find it just doesn't have enough life left in it to rise again properly after, but an extra hour or so will probably improve it - I've always found that recipes err on the side of speed.  

For a 2 hour prove time, I'd keep it slightly cool but not fridge-cool.  Since you're using a very wet dough, you will find it gets a little stickier the longer you leave it, so might need slightly more flour when shaping.

Having said that, I've recently been experimenting with really long rise times (12-24 hours, for ciabatta) - I just haven't found a happy medium yet that suits me.