The propane gas detectors in RV's are not sophisticated enough to discern propane from other flammable gases. The basic purpose of the RV units is to warn of the presence of flammable gas, not really detect a specific gas type. Given the fairly basic design there are many things which the detector may respond to. I'm quite certain that some RV anti-freeze makes the list because some do contain alcohol.
As to other triggers. Propane was once a common propellant in aerosol cans. Many manufacturers try to avoid it because it is flammable, but it is not uncommon to find it in your household products. In some cases the products themselves include alcohol in the ingredients.
Some more detail is below for those who may be interested. vic
Caution and Environmental Hazard
Many propellants are flammable, so it's dangerous to use aerosol cans around an open flame. Otherwise, you might end up with an accidental flamethrower. Another possible danger is inhalation: Some aerosol cans, such as whipped-cream containers, use nitrous oxide, which can be harmful if inhaled in mass quantities. To learn more about the propellants used in aerosol cans, check out this site.
Up until the 1980s, a lot of liquefied-gas aerosol cans used chlorofluorocarbons (CFCs) as a propellant. After scientists concluded that CFCs were harmful to the ozone layer, 70 nations signed the Montreal Protocol, an agreement to phase out CFC use over the next decade. Today, almost all aerosol cans contain alternative propellants, such as liquefied petroleum gas, which do not pose as serious a threat to the environment.
Liquefied Petroleum Gas (LPG)
Aerosol propellant grade LPG consists of high purity hydrocarbons derived directly from oil wells, and as a by-product from the petroleum industry.
They consist of a mixture of propane, isobutane and n-butane. These propellants are used in most aerosols today, and have been used for many years in household aerosol products.
These gases are flammable, and this is reflected in the classification of aerosols which contain them.
Di Methyl Ether
This is an alternative liquefied propellant, and is more common in personal care products, and some air fresheners.
These liquefied propellant gases used to be very common prior to the discovery that they were affecting the ozone layer. They are no longer used in consumer aerosols in the western world. They are however permitted in inhalation aerosols, as used in the treatment of asthma.
Non-soluble compressed Gasses. (e.g. Compressed Air and Nitrogen)
These are sometimes seen in consumer products, and are an environmental alternative to LPG.
Soluble compressed Gasses (e.g. Carbon Dioxide)
This is another alternative to LPG, but has limited use, mainly with alcoholic systems, such as air treatment products, deodorants and personal care products.