Whether you are a monarchist or republican, most will consider this a time to reflect on an incredible life of service.
But some will want the Queen's passing to signal the end of the institution itself and will think this the perfect time to make themselves heard.
In response to the occasional booing or placard-holding, police have a set of choices: ignore it, try to move the protester on or, in some instances, make arrests. But the question is what should they do?
As the Queen's coffin made its way up the Royal Mile in Edinburgh, a young man near the barrier heckled Prince Andrew, who was walking behind.
Many in the crowd responded by trying to drown him out, chanting "God Save the King".
Someone then decided they had had enough and pulled him backwards to the floor by the collar.
On the pavement behind, a police officer intervened to try to calm the situation. Tempers among the public were raised and some pushed the protester as he was steered away down an alley.
"I've done nothing wrong!" he said. Later, he was arrested.
I showed footage of the incident to police officers patrolling outside Windsor Castle. "The problem is sometimes you have to detain people for their own protection," one said.
In Scotland at least, two people have not only been arrested but also charged with breaching the peace over royal protests.
One was a woman holding an anti-monarchy placard among a crowd of people who had turned out for a formal proclamation of Charles as King in Edinburgh on Sunday.
In Oxford, a man was seemingly arrested for making a single comment. Symon Hill said he happened to be passing the King's proclamation on Sunday and shouted "Who elected him?"
He was handcuffed and arrested and said he was shaken by what happened.
"Are we really in a place now in 21st-century Britain where a new head of state is proclaimed, we are told to accept this person without any question, and somebody who speaks out against it is dragged off and arrested?" he asked.
"I felt like I'd slipped into the 16th century for a minute."
Thames Valley Police said: "A 45-year-old man was arrested in connection with a disturbance that was caused during the county proclamation ceremony of King Charles III in Oxford.
"He has subsequently been de-arrested and is engaging with us voluntarily as we investigate a public order offence."
Policing events leading to the Queen's funeral is a large and complex operation and there are new laws around protests.
The Police, Crime, Sentencing and Courts Act, which became law this year, gives police more power to disrupt protests deemed to cause "significant impact" on those near by.
'Intimidation, harassment, alarm or distress'
A government factsheet states that "impact" is defined as intimidation, harassment, alarm or distress, with the police then having to consider whether the impact is "significant".
Interpretation of that clearly depends on the circumstances and sensitivities of the situation. What is complicated in this instance is that two things are happening at the same time.
It is both a moment of national mourning, but also a new King has been proclaimed. So, it is a big constitutional change during a time of high emotion.
Graham Smith, from the pressure group Republic, said: "This is absolutely the time to talk about the future of the monarchy because we have a new monarch. Charles has become King without consent, without discussion or debate.
"It has just happened automatically and there is no effort to have a serious debate about that, and that is completely wrong.
"The arrests of protesters over the past 24 hours have been absolutely appalling. The police should be ashamed of themselves."
But many people who were coming to pay their respects in Windsor said this was not the week for protest.
"They wouldn't do it if the lady down the road died. We are talking about the monarch of this country who's been around for 70 years," a man who had travelled from Dorset to lay flowers at the castle said.
"I think that is just disrespectful."
"Disrespectful" was a word used by many, "crass" was another, though some still felt people should not be arrested even if their comments were offensive.
Hereditary transfer of power is something this country has not seen in 70 years. It is bound to have a mixed reception.
Several protest groups have said they will not campaign during this time of mourning.
But some people will, and it is the police, in the first instance, who will have to decide what is and is not appropriate.