Ask HN: Anyone also seeing an increase in scams when raising funds?

I'm a co-founder of a startup and we already raised money a couple times - still seed stage. Recently we saw a sudden increase in scam artists approaching us. Of course this is a small sample but I wonder if other founders here are seeing the same pattern? Also I want to explain the scams so people are aware of them.

1 - The bitcoin Russian millionaire:

We were approached by two people telling us they represented an investor from Russia which was interested in our company and wanted to invest $1 million. We ended up meeting them in person and they told us who the investor was but we never got to talk to him directly. They said such investor made big money in bitcoin and was looking to invest in several companies. We did some online search and the information matched somehow. Next they wanted us to deposit 75k in a bitcoin wallet so they could use it as proof of collateral. By then we got wary of the whole situation, but because we met them physically and they seemed to know about our company, product and industry we thought it could be legit. They offered to setup a bitcoin wallet for us which of course we refused. We setup the wallet and send them a small transaction so they could identify us and see our balance for the 75k. Their next move was to say that our wallet was no good and it had to be setup in a specific app and then we knew it was a scam. I'm not 100% sure how they planned to steal our money. We think they might have hacked one of our phones before approaching us. They seemed to know what they were doing and looked like nice and educated people.

2 - Old school scam:

Through our network we were referred to an investor. He said typically he likes to lend money first to the company and later he comes in as an investor. We received the contract terms that looked pretty reasonable. Once we tried to move forward he started asking us to cover his "cost" first. Clearly a scam (not even a very elaborated one).

Anyone here have similar stories?