In some cases (when the mission triggers are straightforward), this is simple to do. But there could also be an excessive amount of information given (if a lot of missions stop spawning after researching X), so this could be difficult to implement. Also it could be difficult to figure out in which report this should be given if there are multiple triggers that need to be satisfied.
In the particular case of ski resort missions, the mission triggers are also quite complicated.
true Cover: Sportsmen
false Cult is contained
and:
true Cover: Sportsmen
true X-Com Summary Report #3
false Black Lotus Psi Generator
false Red Dawn Memory Card
false Church of Dagon Statue
false Brainer Cracked
This also shows the latter definition is probably not working as intended. This is because you can't get X-Com Summary Report #3 without getting "Cult is contained", which is fulfilled by any of the latter four, but then in the second mission script at least one of the "false" statements is going to be true. Therefore, as far as I can see, the second mission script will never get triggered.