My patent lawyer told me to, but generally no. If I know the person ahead of time I just ask them to keep it to themselves. Plus I know VCs wont sign NDAs, but I would get someone to agree verbally to keep it to themselves.
Like Oculus did and got bought by FB.
Companies aren't interested in ideas, they want something they can drop in or can see using in 6 months.
* I have over a dozen patents. Learned this the hard way.
I am not a lawyer, but in my understanding, once you file, you have a priority date.
I hold an Australian patent with a US one pending. Both trace their priority back to 2012, when I made an initial filing through WIPO.
For each national patent granted, my patent coverage is backdated to 2012.
Either your idea is patentable, in which case, you might as well brag. Or it's not, in which case, you might as well pretend to brag.