TIFU by casually taking photographs and videos walking around a secure US Consulate Embassy

So this location was of US Embassy / Consulate is the middle of a busy bustling street, to the opposite of which there is a big mall, a convention center, big bank buildings etc. etc. in city 2500kms from my home, I knew no-one in this location.

I was there to accompany my family member for a US Visa interview, although it was written on the walls that photography is not allowed, it was too small for me to notice and there were no verbal announcements. So, I kept on taking casual photos and videos, was on WhatsApp video call showing around, was sharing photos / videos with other members of family etc. etc. They made people to stand on the opposite side of the road from the US Consulate.

Suddenly, the US Consulate security team spotted me and asked me to come to them, I refused initially then they grew in number and accompanied by local cops. I quickly realized the fuckup, so while they were slow chasing me, I deleted most of WhatsApp forwards. To buy time, I kept on debating about their authority to ask me for ID, or hand-over my phone, and my rights of free expression & movement. My goal was to let my family member appear for an interview and not get fucked up due to this issue (we've been waiting for long for this day). Eventually they took me to their heavily fortified security office, took my phone, IDs, performed a background check, made me sit in a detention-like cell / room for 2 hours having a dome camera pointed at me, came back and asked me if I was sharing photos with anyone. You know my answer, so then they started checking my phone. Remember I had deleted WhatsApp forwards, but the fucking Android keeps the media in the gallery in the "WhatsApp" folder. So the officer asked how come there are images and videos in this folder but cannot be seen in WhatsApp to any contacts. I became technologically innocent and claimed I don't know how technology works but it ain't me and that he can delete these. He did delete everything that belonged to that place and let me leave just in time to receive my family member. He mentioned that such kind of a situation can become serious if one has shady background or incidents of this kind in the past. So, with an unexpected TIFU feeling, I survived.

TL;DR: Do not take photographs or videos at or around US Consulate / Embassy. Not sure if same rule is applicable across other similar places.

Curious to know if any of you ever had such an incident?