Visas are one thing you do have to be careful about when travelling standby. If you are going to a country like Russia where the visa is date specific, you will want your exit date to be showing at least a few days later than when you actually plan on making your return flight. You dont want to get bumped and have a visa expire.
Also, nonrevs have to keep in mind that visas, rental cars, and places to stay cost money too, so one has to plan their flights carefully. It would be sad to prepay a hotel, car, and visa only to find yourself number 65 on a list on an oversold flight. If you got bumped, you might just have to eat the cost of the visa. Rental cars and hotels are best obtained where you can reserve them without putting down a credit card deposit (such as on expedia.com). That way, if you do not get on, then you can log on quickly and cancel those reservations.
I am very conservative with nonrev travel. You wont usually see me attempting Orlando, Europe, or Hawaii in the summer. Also, it is a prime rule that the return flights home look good before leaving. If the outbound flight(s) are questionable, then it is not too bad. At least if you get bumped, you are still at home. Nonrevs must be very careful and ensure that they get home before it is time to work. There is not much leeway given if you tell your boss that you could not make it because you were stuck somewhere.