We're/I'm (so) glad you could drop by spoken language
Said to someone who visits you unexpectedly or briefly
We're glad you could drop by. Next time bring your kids, too.
'We're glad you could drop by,' my father said to my uncle.
To visit
Go somewhere for a brief visit or purpose
A short visit
You are always welcome to visit
To stay away from someone's house permanently.
If you swallow the bait, you take something that someone offers you, or agree to do something that someone asks you to do without knowing that it is a trick or way of getting something from you.
You can't just do whatever he wants you to do. Don't swallow the bait.