You may choose not to ride and there is no penalty; since you have not paid for the service. However, if you have already tagged your luggage with ME tags at your home airport; your luggage will go along to your resort via ME.
Many people are deceived by the lines; it may look long, but there are several agents and it is surprising how little time it would take. Also, I believe some people have been able to go directly to the bus boarding area, if all your docs are in order. Since they put three resorts on a bus, the buses fill up fairly quickly. Really, with the fact that you don't have to deal with renting a vehicle, it is worth the wait.
I think some of the negative comments you see from people are of their own making.
The first year, I saw a young couple with two young children go into an absolute meltdown. Turns out they didn't even read the packet that came in the mail, so they didn't tag their bags at their home airport. When they were asked for their baggage claim tickets (so Disney could go find their bags) they said they threw them out because the
travel agent said their bags would be taken care of by Disney. Luckily, they had their airline info, and Disney called and was able to locate the bags after about fifteen minutes or so. The husband got snippy with the clerk, saying well, it is about time, we were told all along by our travel agent you would take care of the bags. He also commented how much of HIS time they had wasted.
When they got to the line for the bus, they got flustered when asked for their transportation coupons for each person, etc. in order to board the bus. The wife huffed at the woman and said she didn't have time to look for them - the other clerk had already wasted too much of their time. The clerk insisted they needed them, and the wife finally dumped out half her day bag on the floor in order to find the packet. She shoved it at the clerk and said, "here, are you happy now?"
The clerk was very nice, and suggested if they decided to travel Disney again, their next trip might be more pleasant if they take the time to review the documents before they leave home.
The guy snapped at the poor girl (who I thought was very appropriate in making the comment) that he would never, ever travel to a place that was so disorganized and the staff so rude.
See, sometimes people make their own problems....