My players love putting me in situations where I have to quickly adjudicate without being able to deeply consult the rules. The downside is that we are using 5e, and most of my experience is in 3.x, so it's very easy for me to get things mixed up. The players are happy with the outcome, but I have a feeling this sort of situation will be coming up more often, so I want to be sure I'm not missing something:
Sneaking into town
The level 7 party (rogue, druid, barbarian, sorcerer and cleric) snuck into town unseen by having Insibility cast on the rogue, the druid wildshaping into something small and slipping into his pocket, and the rest hiding in a bag of holding (with just barely enough air to get there). It worked very well, and they managed to get past every patrol and guard (Pass Without Trace + Rogue with sneak expertise = no roll under 30; a few patrols were good enough to spot something that "low" but those rolls ended up being 35+). It was risky, but they pulled it off.
I think everything was "good" from a rules standpoint there, lots of opposed checks and decisions were made to avoid the most populated areas, and they scouted ahead the day before, so they knew the route.
Breaking into the building
When they finally got to the main building where the crown was (a 3 storey manor house) they got in by breaking in through a 2nd storey window with help from their 24 ft ladder (bag of holding :) ) and Mended the glass back to perfection before a patrol came by (they cut a small hole in the glass with a gem and opened the lock, then Mended the piece of glass back in and closed the window).
Technically speaking, the patrol might have spotted the place the ladder was in the ground, but they never got around to that side before the rest of the action happened.
Greater Invisbility was cast on the rogue, who then went downstairs, snuck past the guards (good rolls), and managed to distract them by throwing a coin hard against a door, making the old cook come out and start yelling at the guards for making noise. Rogue snuck into the "Throne Room" where there were four people and a large guard cat (a variant of saber toothed tiger that failed miserably to detect the rogue by smell). His plan was to Move up to the table, grab the crown off of one of the guy's heads, and put it in the bag of holding before running back out the door with his Dash.
My ruling was that grabbing the crown would be his action (and take a melee attack to grab it), that everyone in the room got a new perception check when he got up on the table (they all failed miserably) and once he grabbed the crown it was opposed initiative to see if he got to finish his move. My thought being that the leader wearing the crown would get to react to someone taking it (and everyone else would notice the crown disappearing).
The rogue won initiative handily, and got back upstairs with only the guard cat noticing and chasing him. The whole party managed to get away from the town mostly unharmed, but should I have run the snatch itself differently? The rogue usually runs full speed (3× move) when sneaking, which doesn't seem really stealthy (no books on me at the moment, but in 3.5 that would be a penalty to the sneak check).
Are there any rules that it looks like I am missing in these scenarios? Now that it has worked, I expect it to come up a few more times.