There's an unwritten code for politeness and good manners that we're all taught at some point in our lives.

Since these codes are passed from one generation to another, you wouldn't think there would be people out there who educate others on these rules, but they actually exist.

One etiquette expert took to Twitter to discuss an important issue: Public transport etiquette.

"It's time to revise etiquette for public transport"

We've all been on a crowded bus or subway and seen an elderly, injured, disabled, or pregnant person standing.

Some buses even have signs that encourage people to give up their seat to people who most need it.

Sometimes, someone will offer them their seat, but that's not always the case.

We know that it's the right thing for someone healthy and able-bodied to give up their seat, but the question is, where is the cut-off age?

William Hanson, an etiquette expert and a columnist for the Daily Mail Online, wants to revise etiquette for public transport.

He said during busy times, "children over the age of five should give up (or at least offer) their seats to adults."

Of course, he still believes the same rules apply for pregnant women, the elderly and disabled.

"It's an essential way to teach them respect for their elders," he added

One Twitter user don't disagree with his opinion, but thinks five years old is too young.

But some people think that it's good for children to learn common courtesy at a young age.

Others are completely against this idea.

[H/T: Daily Mirror]

Do you agree with this etiquette expert's opinion?