Yes you are correct.
It is used to tell someone in a strong way that they must do something or that they must stop doing something. It is used to assert something strongly, to decide something, or express your decision.
Examples:
I'm putting my foot down. I want a divorce.(present)
When she started borrowing my clothes without asking, I had to put my foot down.(past)
When Anna came home drunk one afternoon I decided it was time to put my foot down. (Past)
The boss put her foot down and refused to accept any more changes to the plan. (Past)
My mom put her foot down and said I couldn't use the car until my grades improved. (Past)
You can't just let him do what he wants, you'll have to put your foot down.(Future)
"to put your foot down" is used to strongly assert your authority.
Scenario 1
There is a growing problem in our high schools. With the increasing popularity and decreasing price of cell phones, high school students are spending more and more time in class sending texts on their cell phones. Some people think that this is a problem.
Do you think that teachers should put their feet down and stop students from texting during class?
Scenario 2
Young Aaron has been behaving badly all day. He would not eat his breakfast. He threw his toys all over the room during playtime. Aaron disobeyed his mother and spilled his sticky drink all over the good sofa. At nap time, Aaron yelled and screamed at his mother and tried to hit her.
Do you think that it is time for Aaron's mother to put her foot down and discipline her child?
Gerund Form:
Putting your foot down can be considered a strength.
to put your foot down - Examples:
1) I put my foot down and enforce the rules when my child is misbehaving.
2) You put your foot down and say "no" when it is time to assert your authority.
3) He puts his foot down when he has no more patience.
4) She puts her foot down when her husband wants more money.
5) Management puts its foot down when workers take twenty minute coffee breaks.
6) We put our feet down and send the children to their rooms when each of us needs a break from the noise.
7) You (all) put your feet down and make a decision when each of you (all) needs to end a dispute at work.
8) They put their feet down when each of them needs to make a group decision in order meet a deadline.
9) I should have put my foot down a long time ago.
10) I didn't put my foot down, and I gave him the benefit of the doubt.
11) I always put my foot down with men - in business and in personal relationships.
12) She will hit the roof if I put my foot down and it will cause a big issue.
13) I have however, put my foot down with a firm hand and vowed never to visit that particular returns office again.
14) I have put my foot down and do not want any part of him.
15) I put my foot down and said she was having them on.
16) Toyoda was allowed to put his foot down and implement previously unthinkable changes.
17) At that point, Peter decided to put his foot down and leave.
18) Perhaps Nick has the strength to put his foot down if she's going too far out.
19) After the last time, he put his foot down and made her take out insurance.
20) I'd end up with 12 cats if my husband didn't put his foot down every time we hear of kittens for sale.
Best Answer
If by takes an explicit object it designates a place, not a person: "I'll stop by your office and pick up the file."
If by does not have an object, the place is assumed to be a place named earlier, or the place where your hearer is now, or will be found.
The with phrase in the sentence you quote is not part of the stop by construction. It's an adjunct naming the people who will accompany Sam—they will come with him.