Do you trade with strong AI opponents?

I'm always in two minds about whether I should trade with AI opponents who are either better than me or neck in neck in the rankings. For example, things like singing RAs, trading luxuries, etc. On one hand, I benefit from the trade. On the other hand, the AI also benefits from it, and they tend to insist on uneven trades (for example, they might only be willing to sign an RA if I give them an additional 3 GPT).

In such cases, do you trade with them? I'm assuming that there are no weaker civs to trade with.

I do. It keeps them sweet until I can build up. I think they`re more likely to start war if you don`t trade with them (depending on character).

It is something to consider, but I tend to assume on higher difficulties (Immortal+) that the AI already has plenty happiness to spare, so an extra lux trade doesn't really make much difference and I need the smile boost more than they do.

Strategic resources are different though. I'm not sure if AI civs trade strategic resources between themselves. Don't think I've ever seen an iron-less Rome making Legions, for example. Anyone else know if they do?