Of course, Google has some method for dealing with multiple clicks, though I don't know the details. It probably isn't something you need to worry about, as you have little control over what your visitors do. However, you can be penalized if YOU click on your own ads, I believe.
SitePoint has a Google Ads forum where you might get a more definitive answer.
Definitely nothing to worry about and it's quite an irrelevant concern. This is how Google make their money and thousands of companies and individuals use this service to their benefit (including myself). They wouldn't use it if that was a problem. The math is simple - run a campaign, track it, see the results; if it pays off, continue and scale it, if not try to fine tune it and if you can't make anything out of it before you waste your budget, scrap it. The potential is huge though.
Before asking, do a search... if you don't find the answer, then ask The purpose of this forum is to help others in the community, that's why it's called Sitepoint and not Linkpoint. SP Guidelines - No fluff.