Car tyre pressures when towing

Depends what it says in the car's handbook.

I would say that I increase pressures for towing. However the truth is that  I keep my pressure up for towing and as this is at least 50% of my usage with our tow car I leave them up

The average well built male passenger tends to sit respectfully in his seat and does not jump up and down on my tow bar hitch. 

My handbook says the rear tyres should be increased to max pressure shown on the "tyre pressure label".

I do what the car handbook says, solo / light load 32psi all round, full load / towing 35psi front, 44psi rear.

I leave them at normal running round pressures. Had no problems one way or t'other.

If car is loaded for a holiday then as said, do what the handbook says. There may be an additional increase above fully loaded for towing.

IMHO you need the extra pressure to stiffen up the sidewalls of the tyres to help improve stability.

Have always increased to max in handbook when towing and although a little bumpy when travelling solo would rather have that than risk overheating tyres due to low pressure?

Driving a car solo with just 1 passenger with tyres inflated to max is a lot more than 'a little bumpy' .....

It's a real pain to get tyres up and down when solo/towing.

We are two people and still have gear in the boot,

It has worked for us for 7 years and never thought about changing procedure.

I suppose it depends on the recommended amount of increase. Not much difference in solo/2 front seats occupied operation in our case