So now that voting is open for the entries, it seems anyone can vote on games in the jam as long as they create an itch account.
Is there any guarantee against fraud? What is to stop someone from creating multiple accounts to vote up their game?

I think its an honor system. I doubt the contest judges have control over it sadly. I thought of this too.

Itch has protections set in place, checking ips and such, and we'll definitely look for any odd results (can't go into details on what constitutes odd since that gives people who want to cheat more ideas of what to avoid doing), but the truth is that almost no form of public voting online is foolproof unfortunately. So it is what it is. But we are attempting to curtail it as much as we can.

Yep, the problem is that in order to make it foolproof, you'd need some rather insane methods that would cause most people to avoid voting.

That said, there are some rather iffy entries.

Oh okay. One of my friends played my entry on my computer and then created an itch.io account, and then logged into it on my computer to rate it. She doesn’t have a working computer so I told her to do that since she seemed interested in rating it. When you check the ips, is that gonna be a problem since the rating was done by my friend on the same computer? 

I doubt it would be a problem to have a friend rate it once from your ip. The problem occurs when multiple friends do that.

Absolutely not. You can promote your game as much as you want. You can even ask people to rate it honestly after playing, you just can't ask people to just rate it 5 stars without playing it.

ok thank you

I think the reason there are three prize pools is because a People's Vote can turn into a popularity contest at times. I also do indie comics and when awards, contests, or Kickstarter seasons roll around, people who have these massive pre-existing followings (which, fair enough, they've had to build up in the first place) just dominate. People blindly put their vote in for their favourite person out of a sense of loyalty and it quickly stops being a qualitative assessment.

Sadly, the only recourse is often to fight fire with fire. Tell your friends, family, Twitter, Instagram, etc followers that you've entered, ask them to give the game a try and, if they like it, give it a rating. I think that's the key thing, asking them rather than telling them. In the comics world I've seen some shady tactics where they've said "Oh, vote for my comic, send me the proof, and I'll ping you a free copy of this other comic I made!" or offering a free sketch or what-have-you.

Fingers crossed, everyone plays a clean game here. That said, there are already some entries that'll get disqualified for breaking "Development on contest entries MUST be started after the beginning of the contest (October 29th, 2018)." (mostly games that seem to have been submitted for multiple jams scattershot without thought to the rules or relevance of each jam rather than games that were tailor-made specifically for this jam).

Time will tell. For now we have to trust the team behind the contest and let them do their jobs. :)