Why would you suggest someone use an unreliable, non-optimal system? The purpose of a using a fixed gear is to be able to apply reverse torque to the rear wheel via the pedals. If that isn't the intention, then one is better off with a single speed freewheel and brakes.

It is possible to use loctite to help retain a fixed rear sprocket, if no serious reverse torque is applied, but that somewhat defeats the purpose. The key word in the post was reliably, along with an explanation of the principle involved. So if one wants an unreliable, cheap alternative one is free to do so, but I will never advise it.

BTW- it isn't a case of Murphy's Law but if one relies on loctite to hold a fixed sprocket, it is most likely to fail at the worst possible moment, when you're counting on the reverse torque to stop or control the bicycle. Even if you have a brake, the time and distance lost can become critical.

IMO- only someone who's ignorant or foolish would set up a fixed wheel bike without a track style hub designed for it. Feel free to dis-agree it's only an opinion.