Sorry for the delay getting back to you. The problem with leaking is with the metal "flexible" spouts (never tried plastic). They flex once or twice and then leak and snap. I had one snap and the end fall into my sailboat tank and had to take half the boat apart to get it out. I do a lot of atving and my colleaques have constant problems with the flexible metal ones.
The spout that the military issues is a short fixed steel spout you could run over and not harm it. It snaps onto the can just like the lid does and makes a very tight seal. I have seen people abuse the hell out of these things with no problems. That is the good news; the bad news is they are hard to find on line. I now have two and would buy third if I ould find one.
Conversely, the old WW II type had a long flexible metal hose. Eventually, they too would leak but there used to be a lot of good civilian substitutes.