^ Regarding your last question about raising suspicions:
It wasn't clear from the original post whether financing would be involved.
If financing would be involved, a high earnest money deposit would be suspicious because there would be little to no reason to do so, and in fact reasons not to do so. People who do odd things with money for little to no apparent reason are nearly by definition being suspicious. Even if no fraudulent intent is involved, it makes the other person wonder if they're getting scammed somehow and just can't figure out how.
If financing would not be involved and it is just an all cash deal, that would surprise people around here (doesn't happen that much) but not be suspicious.