Spot on. I knew several members of the second "reptiles" team, and was even recruited to join them (they typically sought out people who are strong in engineering or math, who also have a boisterous personality, which, I'm told, I have =)
The managers had salaries that ranged in the $150k ~ $200k range (including bonuses)... where as the players (spotters and the BPs) were typically brought on as 1099-MISC independent contractors, almost all of whom had regular day jobs (think: engineers or technical managers at Google, Facebook, Apple, etc.) As a spotter or BP, you had to commit to 3 weekend trips every 2 months (with preferences to the long holiday / 3-day weekends), and during the trips you had to have 3 12-hour shifts, with short breaks in between for eating, sleeping, etc. Pay for the independent contractors were a guaranteed $75/hour for hours worked during the weekend, plus a small percentage (I believe it was something like 1.5%) of the total earnings from a weekend's trip (if any), split evenly among the team members that attended that trip. (Travel, food, accommodations, transportation, etc. were all covered). The players were not penalized if the trip ended up having losses.
For the managers, it was a regular job. Averaged out to about 40-50 hours per week, and they were making a decent salary at $150k ~ $200k. But considering that they were all 8-12 years out of college, graduated from MIT or another elite university with an engineering or math background, and living in the SF Bay Area (no, they were not in Las Vegas as "21" or "Bringing Down the House" would have you believe), most of their cohorts were likely making similar salaries at regular, more "mainstream" companies in Silicon Valley.
For the BPs and spotters (e.g. the 1099-MISC contractors), it definitely was decent side income. From talking with my friends on the team, it was pretty mentally grueling ("the Monday or Tuesday after I get back to work I'm a total zombie")... but the side income (usually about $3000 ~ $3500 before taxes per weekend trip) was definitely nice to have, especially for engineers who are maybe making $120k or so with their "day job", the 40~50% or so bump in salary was definitely enjoyable.
But as you can see with these numbers, they were definitely not breaking the bank with any of the money they were making here... definitely not enough to self-fund any future entrepreneurial activity.
And case in point: as the team has now ramped down, a majority of these people ended up going to get MBAs at the various top-10 business schools across the country (Sloan, Wharton, Haas, HBS, Stanford GSB, and of course Kellogg), kinda like everyone else who pursued a more "mainstream" career track.