How to set 'constrain proportions' as default behaviour in Illustrator?

Hi,

I've been using Photoshop and learnt to constrain proportions WITHOUT using the shift key as that is the default behaviour.

Now that I am using Illustrator it's the opposite way round, and I keep forgetting and having to undo lots of work as I've distorted things without noticing when I resized them.

Is there a way to control an object so that it will only drag scale proportionally (and not having to keep applying the setting)?

And / or is there a way to set a preference so that drag scaling will automatically be constrained?

Thanks