I just wanted to add something to SueM's very insightful post. (thank you by the way).
Even for rides like the Jungle Cruise, that does not have mainstream acess (i.e. they have a separate wheelchair entrance toward the exit). It is vary rare, that a party with a wheelchair can come up to the ride be ushered directly to this entrance. In 90% of cases, the Cast Member will instruct the guests to either (a) get a fast pass and come back when the fast pass window opens, at which point they will be given access to the wheelchair que. or (B) The Cast Member can give the party a special ticket (sorta like a fast pass), that instructs them to come back in a certain amount of time (usually what ever the wait for the standby entrance is), at which point the wheelchair party will be directed to the wheelchair line.
Therefore, nobody in a wheelchair or
ECV (unless they do have a GAP-FOTL pass...which is very rare) can ride the Jungle Cruise without waiting at least as long (often longer) as the other guests. (Actually, they usually wait longer, becuase most of the time only one boat is stopped for wheelchair guests, and there is only one boat that can accomidate a single wheelchair for those guests who can not transfer down into the boat).

Just thought I'd like to add my part, to try to dispell any rumors that guests in wheelchairs and ECV's get to skip the lines

.
Also, as a cast member, I've noticed this policy only annoys (sometimes angers) the guests who did rent a wheelchair ro ECV in an attempt to skip the lines. Guests who legitimately need the wheelchair for a member of their party are (for the most part) extremely understanding. On behalf of all former and current cast members - THANK YOU!