It had the effect of flooding it with 4 and 5 star reviews from people who hasn't been around long enough to see any downsides to their job.
Meanwhile, as the company began imploding, the folks jumping ship mostly didn't bother to write a 1 star review on the way out.
Definitely rubbed me the wrong way, but besides that they were really great people. I don't know if they realize what bad taste this is, just don't care, or if it's really just one person with too much influence creating policy.
This was a while ago, so I can only imagine it's become more prevalent. I've come to believe this is pretty much accepted behaviour for SV companies, and I wouldn't put much weight into Glassdoor reviews beyond just checking for red flags.
On more than one occasion I've seen a blistering one star review, followed by a bunch of positive reviews that all came in within days. It was clearly a situation where someone at the company saw the low score, had an "uh-oh moment," and called in the cavalry to write positive reviews.