Haiga,
I sometimes think of these as elements in a spy novel... the number one issue isn't to get a peek or get a good recording but to NOT be discovered.
Back in the day when I was more active at this hobby

I confess to losing a rig or two. For me, that was an inexpensive digital voice recorder and a microphone. If ever that happened, I shut down the project and went away.
I've only had two instances that required a more rapid retreat... again, several years ago -- a regular exercise program is a health smart choice and comes in handy when you have to take to your heels.
I recall the old Spiderman comic books -- he had "spidy-sense" -- some early indication that something was wrong. No superpowers here but I've aborted several observation attempts just because it "felt" wrong. Don't know what I missed but know that I've not spent time with the authorities.
Finally, I don't ever get in a spot without a planned "if X happens, I do Y" - acting just a bit "off" in a hotel corridor can be a handy -- not dangerous "off" but enough that you're a problem that they don't really want any part of...
Had a curious guy approach me in a corridor - he'd seen me walking and hanging around in the hallways on a couple of different floors - I was in "survey" mode at the time. He was a guest not an employee of the hotel -- He wanted to know "What the fuck are you doing?" <he'd been drinking a bit> -- I looked at him with a shocked expression and said in a low whisper - "You can see me?" - not the response he was expecting... I followed up with a quick look around and whispered, " When did get the chip out of your head?"
He looked confused and a little unsure... I followed up with the clincher -- " No, don't tell me - If I'm captured, they'll find out. The men with the black suitcases are in room (I don't recall what room number I gave him ) -- I'm in room 222 (not my room or floor btw) and have the radon detector on." I turned to go, motioning him to follow me. "Come on we'll be safe in my room". --- He backed away -- saying something like -- "No, dude. That's okay - you go ahead."
I said "Ok, but be extra careful." -- He went down the corridor, I went to the stair well and retreated back to my room. Packed it in. Didn't need him getting the hotel staff involved.
I keep this story ready in case a guest gets curious -- if he'd had agreed to come to my room - I'd have said great but that we'd have to take different routes to avoid notice -- he'd go one way and I'd go another.
Reg