Given a travel related situation, and given a specific question about the situation, summarize the question into a title

[Q]: In Louisiana, USA it's widely understood (unofficially) that one can travel 5mph above the speed limit without receiving a speeding ticket.

Does this rule apply when traveling the rest of the States?

[A]: Do any States in the US give traffic tickets for 5 mph above the speed limit?

[Q]: I am a British citizen and I'm planning to travel from the UK to Cuba, stay for a couple of days and then fly directly to Orlando from there. I will then fly back to the UK from Orlando. (Note: this is not a trip operated by a third party, I will be booking flights and accommodation myself).

There have been many threads about this on TripAdvisor in the past, with some people suggesting that American citizens have to declare the reason for their visit and that the same applies to a British citizen travelling from the USA to Cuba.

However, I am struggling to find information for travel in the reverse direction (Cuba to USA) for British citizens. A lot of the information online seems to have been given prior to Trump's amendments to the policy regarding travel to Cuba.

I'd like a more concrete idea of the procedure and if there are any other documents (besides ESTA for the USA and Cuban tourist card) that I might need.

[A]: What restrictions can be expected travelling UK -> Cuba -> USA?

[Q]: There are many times when I'd like to jot a short note in my passport. For example, the business purpose of an entry into a country -- or for countries with automatic passport control and when I don't get a stamp, I'd like to notate my entry and departure.

Can one write in one's own passport? I wouldn't of course write over any stamps, but I might write near them. Or could I use a back page as entry and departure dates?

Yes, I could use a separate piece of paper or a computer file, but having them all in my passport would be handy -- especially when a border officer asks where I've been and why.

And if the laws vary by country, can you note this in your answer? Would it matter if my notations were in ink or pencil? These aren't doodles but business-like annotations and lists.

[A]:
Can I write notes in my passport?