Papabravos point is a very important one. Interference is a big problem in simple systems and often pushes designers to more elaborate protocols just to avoid false signals. For example, it will be necessary to come up with a way that insures that several jetskiers, all using exactly the same system, can be close to each other and not suffer a fault due to inteference. Well, that is if you are making more than one. If not, then this is less of an issue. There is also the problem of multipath that could affect reliability, but perhaps the careful choice of frequencies will minimize this. Again, if you're only making one, then don't worry about this next thing, but if you want to make a product out of it, then the next big thing is that you have to work within government radio regulations which are quite restrictive. These regulations might force you into specific frequency bands, where you have to share with others and the interference they bring.
So, what kind of range are you thinking of? Trigger in, say, 30 feet?