It was unquestionably impolite and very chutzpahdig to do this. There is IMO nothing wrong with a limo however, as long as someone is willing to foot the bill for it. The chosson’s best friend usually makes the arrangements and asks other close friends (and ONLY them), if they would like to chip in tzu shteier for it. My son has always taken this task upon himself to make the arrangements for ALL his close friends, and covers whatever portion is not chipped in, and that is his wedding present to the couple. Just about EVERY Yeshivish couple in his chevrah has enjoyed this gift, and all the friends are happy to contribute to it.
The chosson and kallah are usually exhausted from the wedding, and the limo makes them truly feel like the melech and malka that they are supposed to be on their wedding day. And while I personally went back to my apartment with my new husband, in our clunker of a car, the times they are a-changin’ (and if I had it to do again, I would possibly LOVE to have gone to a hotel in a shiny white limo). BTW, some pretty unmentionable things also happen in people’s apartment buildings and in their very own soon-to-be-filled-with-kedusha apartments as well, from the former tenant’s who lived there (much like the former hotel guests who rented the room). Kedusha is what YOU can bring to a place that has none to begin with.
If you do not want to go in a limo, then by ALL MEANS do not do it. But don’t run to ascribe goyishe zachen to a very nice and thoughtful gesture on the part of the friends of the newlyweds. I do agree 1000% that it was a tacky and rude thing to approach guests for money at the wedding. This is usually discussed with the friends in advance of the wedding. Kids can be quite thoughtless sometimes. What a shocker!